Documentation: Census 1980
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Publisher: U.S. Census Bureau
Survey: Census 1980
Document: Summary Tape File 3
citation:
Social Explorer; U.S. Census Bureau; Census of Population and Housing, 1980: Summary Tape File 3 [machine-readable data file] / conducted By the U.S. Bureau of the Census. Washington: Bureau of the Census [producer and distributor], 1982.
Chapter Contents
Glossary
Gas
Summary Tape File 3
Summary Tape File 3 -- Part II
Information applicable to Summary Tape Files 1-5.
Overview
1980 Census Summary Tape Program
Computer-readable data from the 1980 census Include both summary data and microdata. Summary data include Summary Tape Files (STF's) 1 to 5, which are generally comparable to the First Count through Sixth Count files from the 1970 census. In addition to the files in the STF series, other summary data released by the Bureau include a P.L. 94171 Population Counts file for use in reapportionment/redistricting (released in February/March, 1981) and the Master Area Reference File which provides geographic items from STF 1 and selected population and housing items (all individual State files released beginning September 1981). All of these files contain data summarized to various levels of geography. Microdata files, on the other hand, contain disclosure- free household and person records from the census. These files are similar to the 1970 Public Use Sample files and will be available in mid to late 1982.

Content and Geographic Coverage of Summary Tape Files
Summary Tape Files vary by summary level of geography, detail of information, and whether they include 100-percent or sample data. STF's 1 and 2 provide data based on the set of census questions asked of all persons and housing units. These data are 100-percent data. STF's 3, 4, and 5 are based on sample data. These data are estimates based on the responses of a sample of the population and housing units and contain more extensive housing and population information. In 1980, the sampling rate was 1 in 2 in governmental units estimated to have less than 2,500 inhabitants and 1 in 6 elsewhere. Overall the sampling rate was approximately 1 in 5. The Bureau's 1977 population estimates were used to determine the sampling rate for a given area.

The geographic detail of STF 1 is the maximum possible detail available from the census: data for individual blocks in block- numbered areas and for enumeration districts outside block-numbered areas. The lowest level of geography provided by STF 2 is census tract, or minor civil division/census county division (MCD/CCD) and places of 1,000 or more inhabitants in nontracted areas. The lowest level for STF 3 is the block group or enumeration district, while the smallest geographic unit for STF 4 is census tract, or MCD/CCD and places of 2,500 or more inhabitants in nontracted areas. STF 5's lowest geographic level is the standard metropolitan statistical area (SMSA), central city(ies), other places of 50,000 or more inhabitants, and counties of 50,000 or more inhabitants.

STF's 1 to 4 each consist of multiple files labeled A, B, and C. Each file features specific levels of geography. Figure 8 details the geographic levels on each STF.







For comparison purposes, STF 1 is similar in subject matter and geographic detail to the First and Third Count files for 1970. STF's 2 and 4 are roughly comparable to the 1970 Second and Fourth Counts, respectively. STF 3 is comparable to the 1970 Fifth Count, while STF 5 corresponds to the 1970 Sixth Count. To summarize, STF 1 contains more detailed geography but less subject matter detail than STF 2.

Similarly, STF 3 contains more detailed geography but less subject matter detail than STF 4. STF's 1 and 2 contain complete count data, while STF's 3 and 4 contain sample estimates. Finally, STF 5 contains sample estimates aggregated to a higher level of geography than the other files, but which are presented in the most subject matter detail.

1980 Census Maps
Users may need certain types of maps for the geographic area(s) they are extracting from the file(s). To determine which maps best define the geographic area(s), compare the geographic coverage of each file (see Appendix A) with the description of each type of 1980 census map (see below).

The maps used in conjunction with the above summary tape files consist of five basic types: county maps, place maps, place-and-vicinity maps, Indian Reservation maps, and Metropolitan lap Series (MMS) or Vicinity Map Series (VMS). Ordering information for these maps may be obtained from Data User Services Division, Customer Services (Maps), Bureau of the Census, Washington, D.C. 20233.

All five map types have several characteristics in common:

--To improve legibility, most 1980 maps are at a larger scale than were the comparable l970 maps.

--Symbols used for the various boundaries are consistent for all five types of maps.

--Names, identifying numbers, and boundaries are shown 'where appropriate on al1 maps for counties and equivalent entities, minor civil divisions (MCD's) or census county divisions (CCD's), places, American Indian reservations and Alaska Native villages, census tracts or block numbering areas (BNA's) where present, enumeration districts (ED'S)(in those areas which are not block numbered), and blocks.

--All maps show metric, feet, and mile scales.

--All maps containing block-numbered areas will be available from the U.S. Government Printing Office.

The following paragraphs present a brief description of each type of map.


County Maps
County maps are the backbone of the Bureau's map coverage. Theoretically, with a complete set of these maps the overa11 picture of the census geographic framework for the entire United States and its possessions is shown. Most maps in the county series are at a scale of 1 inch:1 mile. Most county maps are created by superimposing boundaries for most areas for which data are tabulated on base maps supplied by State transportation or highway departments. There are approximately 5,500 county map sheets for 1980. The following geographic area boundaries are defined on county maps where appropriate: State, county, minor civil divisions (MCD's)or census county divisions (CCD's), places, American Indian reservations, census tracts or block numbering areas (BNA's), and enumeration districts (ED's) or numbered blocks. In addition, the locations of Alaska Native villages are indicated. Counties which are totally covered by Metropolitan Map Sheets (MMS) do not have separate county maps.

Place Maps
For places not covered on MMS or VMS sheets where most of the development is contained within the corporate limits of a municipality or within the boundaries established for a census designated place (CDP), the Bureau uses place maps. The scale of the place maps varies from place to place. As with the county maps, most are created by superimposing boundaries for most areas for which data are tabulated on base maps supplied by local or State governments. On the county map, shading is added to indicate the area covered by the place map; i.e., the place map is regarded as an inset to the county map. There are about 12,300 place map sheets for 1980. The geographic area boundaries defined on place maps are the same as for county maps.

Place-and-Vicinity Maps
For places not covered on MMS or VMS sheets which have areas of development outside the corporate limits of a municipality or outside the boundaries established for a CDP, the Bureau uses place-and-vicinity maps. Also included in this are category maps of places which have parcels of land that are not part of the city but are completely surrounded by the city and where two or more places appear on the same map sheet. In all other respects, place-and-vicinity maps have the same characteristics as place maps. As with the place maps, all area covered by the place-and-vicinity map is shaded on the county map and the place-and-vicinity map is considered to be an inset to the county map. There are about 3,300 place-and-vicinity map sheets for 1980. The geographic area boundaries defined on place-and-vicinity maps are the same as those specified for county maps.

Indian Reservation Maps
The Census Bureau developed separate maps for 18 American Indian reservations which could not be depicted adequately on county maps; these maps are very similar in format to county maps. There are approximately 75 American Indian maps and reservation these maps are special insets to the county maps. The geographic area boundaries defined on these maps are the same as those specified for the county maps.

Metropolitan Map Series/Vicinity Map Series (MMS/VMS)
For the Nation's major built-up areas, the Bureau has developed its own malls to provide uniform coverage of the densely settled portions of the counties involved. These maps are referred to as the Metropolitan Map Series (MMS) when the maps cover SMSA counties and as the Vicinity Map Series (VMS) when the maps cover areas which are not in an SMSA. The predominant scale for the MMS and VMS is 1 inch:1,600 feet. In selected areas with very dense development, some sheets are at 1 inch:800 feet; conversely, some sparsely settled areas are mapped at 1 inch:3,200 feet. The MMS and VMS are considered to be insets to the county maps and the areas covered by MMS and VMS are shaded on county maps. There are about 10,400 MMS and VMS sheets for 1980. (In a few instances, these map sheets entirely cover a county, in which case no separate county map exists.) The geographic area boundaries defined on the MNS are the same as those specified for county maps, but also include urbanized areas.

In addition to the five types of maps described above, there are a number of "outline" maps (maps that do not show any data, only the areas to which data can be related) that are prepared and published as part of the various report series. As was the case with the maps previously described, the maps included in the printed reports share common characteristics. Both metric and mile scales are shown. Map scale and content are similar to 1970 except where noted below; however, presentation has been improved to make the maps more readable and consistent from series to series.

The County Subdivision Map Series consists of at least one map page for each State showing the names and boundaries for the state, each component county or equivalent entity, minor civil divisions (MCD's) or census county divisions (CCD's), and all places, both incorporated and census designated. For most States, the scale of the maps requires that they be presented in sections. For 1980, the boundaries (not just the locations) of places with fewer than 2.500 inhabitants are shown for the first time. In addition, the name(s) of adjoining State(s) are shown along with a mark to indicate where the State boundaries intersect. These maps, which are based on the State base maps of the U.S. Geological Survey (USGS) National Mapping Program appear in PC80-1-A. Single-sheet versions of the county subdivision map series will be published at the USGS scale of 1:500,000 (1 inch equals about 8 miles) for all States except Alaska and the outlying areas, and may be fitted together to form multi-State maps. For those States in which American Indian reservations or Alaska Native villages are located, a special version of the county subdivision map showing these entities appears in PC80-1-B and HC80-1-A.

The Urbanized Area Outline Map Series consists of one or more map sheets for each urbanized area (UA) defined on the basis of the 1980 census results. The names and boundaries of all States, counties, MCD's/CCD's, and places on each map are shown, plus the extent of territory defined as "urbanized." These maps appear in PC80-l-A and HC80-1-A. In 1980, the report for each State containing part of a multi-state UA will include the map for the entire UA.


The State SCSA/SMSA Map Series shows county names and boundaries, names and locations of all places with a population of 25,000 or more or designated as the central city of an SMSA, and names and boundaries of standard consolidated statistical areas (SCSA's) and standard metropolitan statistical areas (SMSA's) in the State. For 1980 the name of the capital of the State is underlined. These maps appear in PC80-1-A, B, C, D; HC80-l-A, B; and HC80-2.

The Census Tract Outline Map Series covers each of the areas for which tracts have been defined in 1980. These maps show the boundaries and code identification numbers for each tract; the names of streets or other features used as census tract boundaries; and the names and boundaries for counties, MCD/CCD'S, and all places (not just those over 25,000 as in 1970). Street detail within the tracts is not shown. Separate insets of larger scale than the base maps are included for densely developed areas; however, fewer insets are used than in 1970. Scale varies from map to map. For 1980, tract outline maps will be prepared for tracted counties outside SMSA'S. These maps appear in PHC80-2 and also are available separately.

Map sets will be printed for all block-numbered areas, grouped by SMSA and the nonSMSA remainder of each State. In addition to printed copies of the county, place, place-and-vicinity, and Metropolitan Map Series/Vicinity Map Series (MMS/VMS) sheets having block-numbered areas, there will be an index map depicting the extent of the block-numbered area for the SMSA and State. The SMSA Index to Block Numbered Areas Maps will show the extent of the SMSA; county, MCD/CCD, and place names and boundaries; and the extent of block-numbered area within the SMSA shown by means of shading. The State Index to Block-Numbered Areas Maps were prepared by superimposing the extent of all block-numbered areas in the State over the county subdivision map. This index map will also show the boundaries of the
SMSA(s) in the State so that the reader can determine whether the data for any block-numbered area in the State are available with the SMSA tabulations or the remainder-of-State tabulations.

Relevant Articles and Publications
The following is a list of reference materials which provide additional information concerning the 1980 census.

Census '80 Introduction to Products and Services
This 13 page publication provides a general outline of information and data available from the 1980 census. Limited free copies are available from Data User Services Division, Customer Services (Publications), Bureau of the Census, Washington, D.C. 20233.

PHC80-R1-A. Part A, Text. Users' Guide
This comprehensive guide to the 1980 census data is available from the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. S/N 003-024-03625-8. Price is $5.50. Other parts to the guide will be issued as they are prepared.

1980 Census Update
This publication was issued quarterly film January, 1977 to July, 1981. The updates were intended to keep the data user current on the 1980 census planning and preparatory activities. Back copies are available free of charge from Data user Services Division, Customer Services (Publications), Bureau of the Census, Washington, D.C. 20233.

Data User News
This monthly newsletter provides continuous reporting on Census Bureau programs and products. A subscription is available from the Government Printing Office for $19 a year.

Monthly Product Announcement
This free announcement lists new products released each month from the Census Bureau. These products include publications, technical documentation, data files, published maps, and microfiche. To be added to the mailing list, contact Data User Services Division, Customer Services (Publications), Bureau of the Census, Washington, D.C. 20233.


STF 3 Technical Information
Introduction
The data available on STF 3 are based on the 1980 census sample. The data are estimates of the actual figures that would have resulted from a complete count. Estimates can he expected to vary from the complete count result, because they are subject to two basic types of error---sampling and nonsampling. The sampling error in the data arises from the selection of persons and housing units to be included in the sample. The nonsampling error, which affects both sample and complete count data, is the result of all other errors that may occur during the collection and processing phases of the census. A more detailed discussion of both sampling and nonsampling error and a description of the estimation procedure are provided below.

Sample Design
While every person and housing unit in the United States was enumerated on a questionnaire that requested certain basic demographic information (e.g. age, race, relationship), a sample of persons and housing units was enumerated on a questionnaire that requested additional information. The basic sampling unit for the 1980 census was the housing unit, including all occupants. For persons living in group quarters, the sampling unit was the person. Two sampling rates were employed. In incorporated places of less than 2500 persons (based on precensus estimates), one-half of all housing units and persons in group quarters were to be included in the sample. In all other places, one-sixth of the housing units or persons in group quarters were sampled. The purpose of this scheme was to provide relatively more reliable estimates for small places. When both sampling rates were taken into account across the Nation, approximately 19 percent of the Nation's housing units were included in the census sample.

The sample designation method depended on the data collection procedures. In about ninety-five percent of the country, the census was taken by the mailout/mailback procedure. For these areas, the Bureau of the Census either purchased a commercial mailing list which was updated and corrected by Census Bureau field staff, or prepared a mailing list by canvassing and listing each address in the area prior to Census Day. These lists were computerized, and every sixth unit (for l-in-6 areas) or every second unit (for l-in-2 areas) was designated as a sample unit by computer. Both of these lists were also corrected by the Post Office.

In non-mailout/mailback areas, a blank listing book with designated sample lines (every sixth or every second line) was prepared for the enumerator. Beginning about Census Day, the enumerator systematically canvassed the area and listed all housing units in the listing book in the order in which they were encountered. Completed questionnaires, including sample information for any housing unit which was listed on a designated sample line, were collected.


In both types of data collection procedure areas, an enumerator was responsible for a small geographic area known as an enumeration district, or ED. An ED usually represented the average workload area for one enumerator.

In order to reduce the cost of processing, a scheme was designed while the sample questionnaires were being processes, to select a sample of questionnaires on which the place of work and migration data items would be coded. The sample questionnaires were processed by work units consisting of 1980 census EDs. In work units (EDs) where the place of work and migration data items had not yet been coded, every other sample questionnaire within the work unit was selected for these coding operations. In work units where the place of work and migration data items already had been coded, all sample questionnaires were included in the tabulation.

Errors in the Data
Since the data in this file are based on a sample, they may differ somewhat from complete-count figures that would have been obtained if all housing units, persons within those housing units, and persons living in group quarters had been enumerated using the same questionnaires, instructions, enumerators, etc. The deviation of a sample estimate from the average of all possible samples is called the sampling error. The standard error of a survey estimate is a measure of the variation among the estimates from the possible samples and thus is a measure of the precision with which an estimate from a particular sample approximates the average result of all possible samples. The sample estimate and its estimated standard error permit the construction of interval estimates with prescribed confidence that the interval includes the average result of all possible samples. The method of calculating standard errors and confidence intervals for the data on STF 3 is given below. In addition to the variability which arises from the sampling procedures, both sample data and complete-count data are subject to nonsampling error. Nonsampling error may be introduced during each of the many extensive and complex operations used to collect and process census data. For example, operations such as editing, reviewing, or handling questionnaires nay introduce error into the data. A more detailed discussion of the sources of nonsampling error is given in the section on Control of Nonsampling Errors.

Nonsampling error may affect the data in two ways. Errors that are introduced randomly will increase the variability of the data, and should therefore be reflected in the standard error. Errors that tend to be consistent in one direction will make both sample and complete-count data biased in that direction. For example, if respondents consistently tend to underreport their income, then the resulting counts of households or families by income category will be below the actual figures. Such biases are not reflected in the standard error.

Calculation of Standard Errors
1. Totals and Percentages. Tables A through C, pages 204-208, contain the information necessary to calculate the standard errors of sample estimates in this file. In order to perform this calculation, it is necessary to know the unadjusted standard error for the characteristic, given in table A or B, that would result under a simple random sample design (of persons, families, or housing units) and estimation technique; the adjustment factor for the particular characteristic estimated, illustrated in table
C; and the number of persons or housing units in the tabulation area and the percent of these units in sample, derivable from each STF 3 record. The adjustment factors reflect the effects of the actual sample design and complex ratio estimation procedure used for the 1980 census.

To calculate the approximate standard error of an estimate, follow the steps given below.

a.Obtain the unadjusted standard error from table A or B (or from the formula given below the table) for the estimated total or percentage, respectively;

b.For the geographic tabulation area with which you are working, compute the "percent in sample" by dividing the appropriate unweighted sample count by the corresponding 100-percent count. For person and family characteristics these figures are found in STF 3 tables 2 and 3; for household and housing unit characteristics these figures are found in STF 3 tables 5 and 6.

c. Use table C to obtain the factor for the characteristic (e.g. work disability, school enrollment) and the range that contains the percent in sample with which you are working. Multiply the unadjusted standard error by this factor. If the estimate is a cross tabulation of more than one characteristic, use the largest factor.

As is evident from the formulas below tables A and B, the unadjusted standard errors of zero estimates or of very small estimated totals or percentages approach zero. This is also the case for very large percentages or estimated totals that are close to the size of the tabulation areas to which they correspond. These estimated totals and percentages are, nevertheless, still subject to sampling and nonsampling variability, and an estimated standard error of zero (or very small standard error) is not appropriate.

For estimated percentages that are less than 2 or greater than 98, use the unadjusted standard errors in table B that appear in the 2 or 98 row. For an estimated total that is less than 50 or within 50 of the total size of the tabulation area, use an unadjusted standard error of 16.


As is evident from the formula below tables A and B, the unadjusted standard errors of zero estimates or of very small estimated totals or percentages approach zero. This is also the case for very large percentages or estimated totals that are close to the size of the tabulation areas to which they correspond. These estimated totals and percentages are, nevertheless, still subject to sampling and nonsampling variability, and an estimated standard error of zero (or very small standard error) is not appropriate.

For estimated percentages that are less than 2 or greater than 98, use the unadjusted standard errors in table B that appear in the 2 or 98 row. For an estimated total that is less than 50 or within 50 of the total size of the tabulation area, use an unadjusted standard error of 16.



This method, however, will underestimate (overestimate) the standard error if the two items in a sum are highly positively (negatively) correlated or if the two items in a difference are highly negatively (positively) correlated. This method may also be used for the difference between (or sum of) sample estimates from two censuses or between a census sample and another survey. The standard error for estimates not based on the 1980 census sample must be obtained from an appropriate source outside of this documentation.

a. For the difference between two estimates, one of which is a subclass of the other, use the tables directly where the calculated difference is the estimate of interest.

3. Means. The standard error of a mean depends upon the variability of the distribution on which the mean is based, the size of the sample, the sample design (for example, the use of households as a sampling unit), and the estimation procedure used.

An approximation to the standard error of the mean may be obtained as follows: compute the variance of the distribution on which the mean is based; multiply this value by five and divide the product by the total count of units in the distribution; obtain the square root of this quotient and multiply the result by the adjustment factor from table C that is appropriate for the characteristic on which the mean is based.

4. Medians. For the standard error of a median of a characteristic, it is necessary to examine the distribution from which the median is derived, as the size of the base and the distribution itself affect the standard error. An approximate method is given here. As the first step, compute one-half of the number on which the median is based (refer to this result as N/2). Treat N/2 as if it were an ordinary estimate and obtain its standard error as instructed above using tables A, B, and C. Compute the desired confidence interval about N/2. Starting with the lowest value of the characteristic, cumulate the frequencies in each category of the characteristic until the sum equals or first exceeds the lower limit of the confidence interval about N/2. By linear interpolation, obtain a value of the characteristic corresponding to this sum. This is the lower limit of the confidence interval of the median. In a similar manner, cumulate frequencies starting from the highest value of the characteristic until the sum equals or exceeds the count in excess of the upper limit of the interval about N/2. Interpolate as before to obtain the upper limit of the confidence interval for the estimated median.

Confidence Intervals
A sample estimate and its estimated standard error may be used to construct confidence intervals about the estimate. These intervals are ranges that will contain the average value of the estimated characteristic that results over all possible samples, with a known probability. For example, if all possible samples that could result under the 1980 census sample design were independently selected and surveyed under the same conditions, and if the estimate and its estimated standard error were calculated for each of these samples, then:

(1)Approximately 68 percent of the intervals from one estimated standard error below the estimate to one estimated standard error above the estimate would contain the average result from all possible samples; and
(2)Approximately 95 percent of the intervals from two, estimated standard errors below the estimate to two estimated standard errors above the estimate would contain the average result from all possible samples.

The intervals are referred to as 68 percent and 95 percent confidence intervals, respectively.


The average value of the estimated characteristic that could be derived from all possible samples is or is not contained in any particular computed interval. Thus, we cannot wake the statement that the average value has a certain probability of falling between the limits of the calculated confidence interval. Rather, one can say with a specified probability or confidence that the calculated confidence interval includes the average estimate from all possible samples (approximately the complete-count value).

Confidence intervals may also be constructed for the difference between two sample figures. This is done by computing the difference between these figures, obtaining the standard error of the differences (using the formula given earlier) and then forming a confidence interval for this estimated difference as above. One can then say with specified confidence that this interval includes the difference that would have been obtained by averaging the results from all possible samples.

The estimated standard errors given on STF 3 do not include all portions of the variability due to nonsampling error that may be present in the data. The standard errors reflect the effect of simple response variance, but not the effect of correlated errors introduced by enumerators, coders, or other field or processing personnel. Thus, the standard errors calculated represent a lower bound of the total error. As a result, confidence intervals formed using these estimated standard errors may not meet the stated levels of confidence (i.e., 68 or 95 percent). Thus, some care must he exercised in the interpretation of the data on STF 3 based on the estimated standard errors.

For more information on confidence intervals and nonsampling error, see any standard sampling theory text.

Use of Tables to Compute Standard Errors
1.The table shows that for [Anytown] out of all [329,571] persons aged 18 years and over, [12,524.] speak a language other than English at home. The procedure for obtaining the standard error of [12,524] will be demonstrated.

The unadjusted standard error for the estimated total is obtained from table A or from the formula below table A. In order to avoid interpolation, the use of the formula will he demonstrated here. BY- the formula, the unadjusted standard error, Se, is given by



The standard error of the estimated [12,524] persons aged 18 years and over who speak a language other than English at home is found by multiplying the unadjusted standard error, [247], by the appropriate adjustment factor. Table 2 of the STF 3 record for [Anytown] shows [89,452] as the unweighted sample count of persons. This figure is found to be roughly [19] percent of the l00-percent count of [470.816] persons shown in STF 3 table 3. Table C lists the adjustment factor for the characteristic "Language Usage and Ability to Speak English." The column that gives the range which includes [19] percent in sample shows the adjustment factor to be (I.31 for "Language Usage and Ability to
Speak English." Thus, the estimated standard error is x
or.

The estimated percent of persons 18 or older who speak a language other than English at home is [3.8]. From table B, the unadjusted standard error is found to be [0.l]. Thus, the standard error for the estimated percent of persons 18 or older who speak a language other than English at home is seen to be [1.3] x [0.l] = [0.13].

A note of caution concerning numerical values is necessary. Standard errors of percentages derived in this manner are approximate. Calculations can be expressed to several decimal places, but to do so would indicate more precision in the data than is justifiable. Final results should contain no more than one decimal place when the estimated standard error is one percentage point (i.e., 1.0) or more.

1. In the previous example, the standard error of the [12,524] persons, 18 and older in [Anytown] who speak a language other than English at home is found to be [321]. Thus, a 95-percent confidence interval for this estimated total is found to be

[12,524] - 3 ([321]) to [12,524] + 2 (1321))

or

[11,882] to [13,166].

One can say with about 95-percent confidence that this interval includes the actual value that would have been obtained by averaging the results from all possible samples.

The calculation of standard errors and confidence intervals will be illustrated when a difference of two sample estimates is obtained. For example, the number of persons in [Anyplace] aged 18 years and over who speak a language other than English at home is [12,500] and the total number of persons aged 18 years and over is [250,000]. Thus, the percentage of persons 18 years and over who speak a language other than English at home is [5] percent. The unadjusted standard error from table B is percent. The STF 3 record for [Anyplace] contains [49,000] as the unweighted sample count of persons in table 2 and [350,000] as the l00-percent count of persons yielding a percent-in-sample of [14] percent. From table C, the column that gives the range which includes [14] percent in sample, shows the adjustment factor to be [l.5] for "Language Usage and Ability to Speak English." Thus, the approximate standard error of the percentage (5 percent) is [O.1] x [1.5] = [0.15].

Suppose that one wishes to obtain the standard error of the difference between [Anytown] and [Anyplace] of the percentages of persons who were 18 years and over and who speak a language other than English at home.

The difference in the percentages of interest for the two cities is

[5.0] - [3.8] = [1.2] percent

Using the results of the previous example



The 95-percent confidence interval for the difference is formed as before.

[1.2] - 2 [0.20] to [1.2] + 2 [0.20]
or
[0.8] to [1.6]

One can say with 95-percent confidence that the interval includes the actual difference that would have been obtained by averaging the results from all possible samples.

Estimation Procedure
The estimates which appear on STF 3 were obtained from an iterative ratio estimation procedure which resulted in the assignment of a weight to each sample person or housing unit record. For any given tabulation area, a characteristic total was estimated by summing the weights assigned to the persons or housing units in the tabulation area which possessed the characteristic. Estimates of family characteristics were based on the weights assigned to the family members designated as householders. Each sample Person or housing unit record was assigned exactly one weight to be used to produce estimates of all characteristics. For example, if the weight given to a sample person or housing unit h
The estimation procedure used to assign the weights was performed in geographically defined "weighting areas." Weighting areas were generally formed of adjoining portions of geography, which closely agreed with census tabulation areas within counties. Weighting areas were required to have a minimum sample of 400 persons. Weighting areas were never allowed to cross State or county boundaries. In small counties with a sample count of less than 400 persons, the minimum required sample condition was relaxed to permit the entire county to become a weighting area.

Within a weighting area, the ratio estimation procedure for persons was performed in three stages. For Persons, the first stage employed seventeen household type groups. The second stage used two groups: householders and non-householders. The third stage could potentially use 160 age-sex-race-Spanish origin groups. The stages were as follows:

Persons

Stage I - Type of Household

Group Persons in Housing Units With a Family With Own Children Under 18.
1 2 persons in housing unit
2 3 persons in housing unit
3 4 persons in housing unit
4 5 to 7 persons in housing unit
5 8-or-more persons in housing unit
 
Group Persons in Housing Units With a Family Without Own Children Under 18.
6-10 2 persons in housing unit through 8-or-more persons in housing unit
Group Persons in All Other Housing Units
11 1 person in housing unit
12-16 2 persons in housing unit through 8-or-more persons in housing unit
17 Persons in group quarters

Stage II - Householder/Non-householder

Group  
1 Householder
2 Non-householder (including persons in group quarters)

Stage III - Age/Sex/Race/Spanish Origin

Group White Race
    Persons of Spanish Origin
        Male
1 0 to 4 years of age
2 5 to 14 years of age
3 15 to 19 years of age
4 20 to 24 years of age
5 5 to 34 years of age
6 35 to 44 years of age
7 45 to 64 years of age
8 65 years of age or older
          Female
9-16 Same age categories as groups 1 to 8
 
17-32 Persons Not of Spanish Origin
      Same age and sex categories as groups 1 to 16
33-64 Black Race
      Same age/sex/Spanish origin categories as groups 1 to 32
65-96 Asian and Pacific Islander Race
      Same age/sex/Spanish origin categories as groups 1 to 32
97-128 American Indian or Eskimo or Aleut Race
      Same age/sex/Spanish origin categories as groups 1 to 32
129-150 Other Race (includes those races not listed above)
      Same age/sex/Spanish origin categories as groups 1 to 32


Within a weighting area, the first step in the estimation procedure was to assign each sample person record an initial weight. This weight was approximately equal to the inverse of the probability of selecting a person for the census sample.

The next step in the estimation procedure was to combine, if necessary, the groups in each of the three stages prior to the repeated ratio estimation in order to increase the reliability of the ratio estimation procedure. For the first and second stages, any group that did not meet certain criteria concerning the unweighted sample count or the ratio of the complete count to the initially weighted sample count, was combined, or collapsed, with another group in the same stage according to a specified collapsing pattern. At the third stage, the "other" race category was collapsed with the "White" race category before the above collapsing criteria, as well as an additional criterion concerning the number of complete count persons in each category were applied.

As a final step, the initial weights underwent three stages of ratio adjustment which used the groups listed above. At the first stage, the ratio of the complete census count to the sum of the initial weights for each sample person was computed for each stage I group. The initial weight assigned to each person in a group was then multiplied by the stage I group ratio to produce an adjusted weight. In stage II, the stage I adjusted weights were again adjusted by the ratio of the complete census count to the sum of the stage I weights for sample persons in each stage II group. Finally, the stage II weights were adjusted at stage III by the ratio of the complete census count and the sum of the stage II weights for sample persons in each stage III group. The three stages of adjustment were performed twice (two iterations) in the order given above. The weights obtained from the second iteration for Stage III were assigned to the sample person records. However, to avoid complications in rounding for tabulated data, only whole number weights were assigned. For example, if the final weight for the persons in a particular group was 7.2, then one-fifth of the sample persons in this group were randomly assigned a weight of 8 and the remaining four-fifths received a weight of 7.

Separate weights were derived for tabulating the place of work and migration data items. The weights were obtained by adjusting the weight derived above for persons on questionnaires selected for coding by the reciprocal of the ED coding rate and a ratio adjustment to ensure that the sum of the weights and the complete count total population figure would agree.

The ratio estimation procedure for housing units was essentially the same as that for persons. The major difference was that the occupied housing unit ratio estimation procedure was done in two stages and the vacant housing unit ratio estimation procedure was done in one stage. The first stage for occupied housing units employed sixteen household type categories and the second stage could potentially use 190 tenure-race-Spanish origin-value/rent groups. For vacant housing units three groups were utilized. The stages for the ratio estimation for housing units were as follows:

Occupied Housing Units

Stage 1. - Type of Household

Group Housing Units With A Family With Own Children Under 18
1 2 persons in housing unit
2 3 persons in housing unit
3 4 persons in housing unit
4 5 to 7 persons in housing unit
5 8-or-more persons in housing unit
Group Housing Units With A Family Without Own Children Under 15
6-10 2 persons in housing unit through 8-or-more persons in housing unit
Group All Other Housing Units
11 1 person in housing unit
12-16 2 persons in housing unit through 8-or-more persons in housing unit

Stage II - Tenure/Race and Origin of Householder/ Value or Rent

  Owner
      White race (Householder)
Group         Persons of Spanish Origin (Householder)
  Value of House
1 $ 0 -$ 9,999
2 $ 10,000 - $19,999
3 $ 20,000 - $ 24,999
4 $ 25,000 - $ 49,999
5 $ 50,000 - $ 99,999
6 $100,000 - $149,999
7 $150,000 or more
8 Other Owners
9-16 Persons Not of Spanish Origin
      Same value categories as groups 1 to 8
17-32 Black Race
      Same value - Spanish origin categories as groups 1 to 16
33-48 Asian and Pacific Islander Race
      Same value - Spanish origin categories as groups 1 to 16
49-64 Indian (American) or Eskimo or Aleut Race
      Same value - Spanish origin categories as groups 1 to 16
65-80 Other Race (includes those races not listed above)
      Same value - Spanish origin categories as groups 1 to 16
Group Renter
      White Race
          Persons of Spanish origin
  Rent Categories
81 $ 1-$ 59
82 $ 60 - $ 99
83 $100 - $149
84 $150 - $199
85 $200 - $249
86 $250 - $299
87 $300 - $399
88 $400 - $499
89 $500 or more
90 Other Renter
91 No Cash Rent
92-102 Persons Not of Spanish Origin
      Same rent categories as groups 81 to 91
103-124 Black Race
      Same rent - Spanish origin categories as groups 81 to 102
125-146 Asian and Pacific Islander Race
      Same rent - Spanish origin categories as groups 81 to 102
147-168 American Indian or Eskimo or Aleut Race
      Same rent - Spanish origin categories as groups 81 to 102
169-190 Other Race (includes those races not listed above)
      Same rent - Spanish origin categories as groups 81 to 102
Vacant housing units
1 Vacant for Rent
2 Vacant for Sale
3 Other Vacant

The estimates produced by this procedure realize some of the gains in sampling efficiency that would have resulted if the population had been stratified into the ratio estimation groups before sampling, and the sampling rate had been applied independently to each group. The net effect is a reduction in both the standard error and the possible bias of most estimated characteristics to levels below what would have resulted from simply using the initial (unadjusted) weight. A by-product of this estimation procedure is that the estimates from the sample will, for the most part, be consistent with the complete count figures for the population and housing unit groups used in the estimation procedure.

Control of Nonsampling Error
As mentioned above, nonsampling error is present in both sample and complete count data. If left unchecked, this error could introduce serious bias into the data, the variability of which could increase dramatically over that which would result purely from sampling. While it is impossible to completely eliminate nonsampling error from an operation as large and complex as the 1980 census, the Bureau of the Census attempted to control the sources of such error during the collection and processing operations. The primary sources of nonsampling error and the programs instituted for control of this error are described below. The success of these programs, however, was contingent upon how well the instructions were actually carried out during the census. To the extent possible, both the effects of these programs and the amount of error remaining after their application will be evaluated.

Undercoverage
It is possible for some households or persons to be entirely missed by the census. This undercoverage of persons and housing units can introduce biases into the data. Several extensive programs were developed to focus on this important problem.

  • The Postal Service reviewed mailing lists and reported housing unit addresses which were missing, undeliverable, or duplicated in the listings.
  • The purchased commercial railing list was updated and corrected by a complete field review of the list of housing units during a precanvass operation.
  • A record check was performed to reduce the undercoverage of individual persons in selected areas. Independent lists of persons, such as driver's license holders, were matched with the household rosters in the census listings. Persons not matched to the census rosters were followed up and added to the census counts if they were found to have been missed.
  • A recheck of units initially classified as vacant or nonexistent was utilized to further reduce the undercoverage of persons.

More extensive discussions of programs developed to reduce undercoverage will be published as the analyses of those programs are completed.

Respondent and Enumerator Error
The person answering the questionnaire or responding is the questions posed by an enumerator could serve as a source of error by offering incorrect or incomplete information. To reduce this source of error, questions were phrased as clearly as possible based on precensus tests and detailed instructions for completing the questionnaire were provided to each household. In addition, respondents' answers were edited for completeness and consistency and followed up as necessary. For example, if labor force items were incomplete for a person 15 years or older, long form field edit procedures would recognize the situation and a follow-up attempt to obtain the information would be made.

The enumerator may misinterpret or otherwise incorrectly record information given by a respondent; may fail to collect some of the information for a person or household; or may collect date for households that were not designated as part of the sample. To control these problems, the work of enumerators was carefully monitored. Field staff were prepared for their tasks by using standardized training packages which included experience in using census materials. A sample of the households' interviewed by enumerators for nonresponse were reinterviewed to control for the possibility of data for fabricated persons being submitted by enumerators. Also, the estimation procedure was designed to control for biases that would result from the collection of data from households not designated for the sample.

Processing Error
The many phases involved in processing the census data represent potential sources for the introduction of nonsampling error. The processing of the census questionnaires includes the field editing, followup, and transmittal of completed questionnaires; the manual coding of write-in responses; and the electronic data processing. The various field, coding and computer operations undergo a number of quality control checks to insure their accurate application.

Nonresponse
Nonresponse to particular questions on the census questionnaire allows for the introduction of bias into the data, since the characteristics of the nonrespondents have not been observed and may differ from those reported by respondents. As a result, any allocation procedure using respondent data may not completely reflect this difference either at the elemental level (individual, person or housing unit) nor on the average. Some protection against the introduction of large biases is afforded by minimizing non-response. In the census, nonresponse was substantially reduced during the field operations by the various edit and followup operations aimed at obtaining a response for every question. Characteristics for the nonresponses remaining after this operation were allocated by the computer using reported data for a person or housing unit with similar characteristics.

Editing of Unacceptable Data
The objective of the processing operation is to produce a set of statistics that describes the population as accurately and clearly as possible. To meet this objective, certain unacceptable entries were edited.

In the field, questionnaires were reviewed for omissions and certain inconsistencies by a census clerk or an enumerator and, if necessary, a followup was made to obtain necessary information. In addition, a similar review was performed by hand only when it could not be done effectively by machine.

As one of the first steps in editing, the configuration of marks on the questionnaire column was scanned electronically to determine whether it contained information for a person or merely spurious marks. If the column contained entries for at least two of the basic characteristics (relationship, sex, race, age, marital status, Spanish origin), the inference was made that the marks represented a person. In cases in which two or more basic characteristics were available for only a portion of the people in the unit, other information on the questionnaire provided by an enumerator was used to determine the total number of persons. Names were not used as a criterion of the presence of a person because the electronic scanning did not distinguish any entry in the name space.

If any characteristics for a person were still missing when the questionnaire reached the central processing offices, they were supplied by allocation. Allocations, or assignments of acceptable codes in place of unacceptable entries were needed most often when an entry for a given item was lacking or when the information reported for a person on that item was inconsistent with other information for the person. As in previous censuses, the general procedure for changing unacceptable entries was that was consistent with to assign an entry for a person entries for other persons with similar characteristics. Thus, a person who was reported as a 20-year-old son of the householder, but for whom marital status was not reported, was assigned the same marital status 3s that of the last son processed in the same age group. The assignment of acceptable codes in place of blanks or unacceptable entries, it is believed, enhances the usefulness of the data.

The editing process also includes another type of correction; namely, the assignment of a full set of characteristics for a person. When there was an indication that a housing unit was occupied but the questionnaire contained no information for all or most of the people, although persons were known to be present, a previously processed household was selected as a substitute and the full set of characteristics for each substitute person was duplicated. These duplications fall into two classes: (1) "persons substituted for mechanical failure," e.g., when the questionnaire page on which persons were listed was not properly microfilmed, and (2) "persons substituted for noninterview," e.g., when a housing unit was indicated as occupied but the occupants were not listed on the questionnaire.

Specific tolerances were established for the number of computer allocations and substitutions that would be permitted. If the number of corrections was beyond tolerance, the questionnaires in which the errors occurred were clerically reviewed. If it was found that the errors resulted from damaged questionnaires, from improper microfilming, from faulty reading by FOSDIC of undamaged questionnaires, or from other types of machine failure, the questionnaires were reprocessed.







1 For person and family characteristics, derive this figure from the appropriate STF 3 data by dividing the unweighted sample count of persons (table 2) by the 100-percent count of persons (table 3). For household and housing unit characteristics, derive this figure by dividing the unweighted sample count of housing units (table 5) by the 100-percent count of housing units (table 6).

2 The adjustment factor for this characteristic was calculated as if about one half of the questionnaires had been coded. Thus, the factor will provide a conservative estimate of the standard error in areas where more than one half of the questionnaires were, in fact, coded.

Glossary
The following definitions pertain to data items included in STF 3 and were taken from the 1980 Census Users' Guide.

Ability to Speak English
See "Language Usage and Ability to Speak English".

Access
See "Housing Unit".

Acreage of Property
See "Farm Residence;" "Rent, Contract;" "Value".

Age at last birthday, i.e., number of completed years from birth to April 1, 1980, based on replies to a question on month and year of birth. This item was asked on a complete-count basis.

Because of the central importance of the data on age, the question contains redundancies. The age entry on the basic tape record is derived from the FOSDIC entries of quarter and year of birth. For those persons who do not provide this information but who do provide "age at last birthday," the census enumerator or clerk uses an equivalency table to mark the appropriate FOSDIC circles. The item "age at last birthday" is used only secondarily because of the tendency of some people, in reporting their ages, to round off to "0" or "5" (and to report even rather than odd numbers). The write-in entries of month and year of birth are requested because some people have difficulty with (and therefore skip) the FOSDIC marking system in this question.

Age is tabulated by single years of age and by many different groupings such as 5-year age groups. Basic records identify single years (and quarter years on sample basic records) to 112. Public-use microdata samples show single years and quarters to 99, and 100 years or more.

Median Age
Calculated as the value which divides the age distribution into two equal parts, one-half the cases falling below this value, one-half above. Median age is computed from the age intervals or groupings shown in the particular tabulation, and thus a median based on a less detailed distribution may differ slightly from a corresponding median for the same population based on a more detailed distribution. If the median falls in the terminal category, e.g., 75 years and over, the median is shown as the initial age of the category with a plus sign, e.g., 75+.

Limitations
In previous censuses, undercoverage of the population has been associated with age. Young adults, especially Black males, were missed at a higher rate than other segments of the population. The same is true of centenarians.

Historical comparability
Age data have been collected in each census since 1790. Counts in 1970 and 1980 for persons 100 years old
and over were substantially overstated.

See also: "Age of Householder".

Age at First Marriage
Persons 15 years old and over who had ever been married were asked the month and year of their first marriage. This item was asked on a sample basis.

Age at first marriage is computed as the difference between the date of first marriage and the date of birth. However, since both dates are recorded on census basic records only in terms of quarters, there is some imprecision in the result. For instance, a person born in September 1950 and married in July 1970 would have been recorded as born and married in the third quarter and aged 20 at first marriage, even though the person was actually only 19 at the time.

Public-use microdata include the quarter of marriage, as well as age in whole and quarter years, so that age at first marriage can be figured in terms of quarter years, and so that the interval between marriage and the birth of children can be calculated.

Historical comparability
Obtained in each census since 1940.

Age of Householder
Derived from the age responses for the householders. (See the definition of householder under "Household Relationship.") Age and household relationship were determined on a complete-count basis.

The most frequent applications of age of householder in 1980 tabulations involve only two categories: under 65 years old and 65 years and over. More detailed categories appear among the housing tabulations, for example: less than 25 years, 25 to 29, 30 to 34, 35 to 44, 45 to 59, 60 to 64, and 65 years and over. Age of householder is also derivable from age tabulations cross-classified by household relationship (STF 2). Age of householder is derivable from basic records in single years, 15 to 112. Public-use microdata samples also show single years to 99, but group together householders 100 years and over.

Historical comparability
In 1970 and previous censuses, Age of Head was tabulated instead of Age of Householder (see "Household Relationship").

Age of Structure
See "Year Structure Built".

Aged, Homes For
See "Group Quarters Type".

Air Conditioning
Presence of equipment with a refrigeration unit to cool air in occupied and vacant housing units. Evaporative coolers and fans or blowers not connected to a refrigerating apparatus are excluded, but refrigerating heat pumps are included. This item was asked on a sample basis.

Central system
A central installation designed to deliver cooled air to a number of rooms in a house or apartment. The system may have individual room controls. In an apartment building, a central system may coo1 all apartments in the building, each apartment may have its own central system, or there may be several systems, each providing central air conditioning for a group of apartments.

Individual room unit
An individual air conditioner which is installed in a window or an outside wall, and is generally intended to deliver cooled air to the room in which it is located, although it may sometimes be used to cool more than one room.

No air conditioning present.

Historical comparability
Similar data have been collected since 1960.

Alaska Native Villages
Alaska Native villages constitute tribes, bands, clans, groups, villages, communities, or associations in Alaska which were listed in sections 11 and 16 of the Alaska Native Claims Settlement Act, public Law 92-203, or which met the requirements of the Act and which the Secretary of Interior determined were, on the 1970 census enumeration date (April 1), composed of 25 or more Alaska Natives. This list was reviewed and updated for the Census Bureau by the State of Alaska, prior to the 1980 census, to specifically identify only those entities that were legally recognized as Alaska Native villages.

Data summaries for Alaska Native villages are included in STF's 2B, 2C, 4B, and 4C, and reports PC80-1-B and -c and HC80-1-A and -B.

Population and housing counts for Alaska Native villages are scheduled to be included in a supplementary report (PCSO-S1 series). In addition, a population subject report (PC30-2 series) featuring additional data on Alaska Native villages is also planned. Data for each Alaska Native village can be derived from MARF, STF 1A, and STF 3A by identifying the ED or ED's that constitute the village, and summarizing the data should multiple ED's be involved. (NOTE: Eklutna Native Village is in a blocked area; therefore, data can be derived from block group (BG) summaries for the village.) Each Alaska Native village has been assigned a unique 3-digit code by the Bureau which appears in the reservation code field.

Alaska Native villages are identified on the Alaska subdivision maps in the PC80-1-B and HC80-1-A reports. Alaska Native villages are also shown on Metropolitan Map Series, place, and county maps. It should be noted that Alaska Native villages do not have boundaries that are defined by legal descriptions, and therefore the boundaries shown on the census maps are only indicative of the approximate extent of a village; for those that correspond to a city or census designated place, the limits of such a place are construed to coincide with the extent of the Alaska Native village.

Historical comparability
Data are not available from previous censuses for Alaska Native villages. Some cities and "unincorporated places" (referred to as "census designated places" in 1980) which were identified in the 1970 census may correspond to 1980 Alaska Native villages.

Aleut Population
See "Race".

Aliens
See "Citizenship".

American Indian Language Usage
See "Language Spoken At Home".

American Indian Population
See "Race".

American Indian Reservations
American Indian reservations are areas with boundaries established by treaty, statute, and/or executive or court order. The reservations and their boundaries were identified for the Census Bureau by the Bureau of Indian Affairs (BIA) and State governments. Federal and State reservations are located in 33 States and may cross State, county, minor civil division/census county division, and place boundaries. In tabulations for reservations, tribal trust lands outside the boundaries of reservations (off reservation) are not included as part of the reservations (see below).

Preliminary evaluation of the 1980 census data suggest that counts for a few reservations may be subject to certain limitations or nonsampling errors. Although the various field and computer operations undergo a number of quality control checks to ensure accuracy of the data, available evidence indicates that nonsampling errors are substantial for a small number of reservations. For example, a few reservations have a relatively high substitution rate. A listing of reservations where characteristics for 20 percent or more of the persons or housing units in the 1980 Census were substituted are shown in PC80-1-B reports, Appendix D, "Accuracy of the Data."(For a fuller discussion of nonsampling errors, see the Users' Guide, chapter 6, "Data Limitations," report appendixes on "Accuracy of the Data," or the "Technical Information" section in tape technical documentation.) Additional evaluation of the counts for reservations will be done when more information is available and a fuller explanation will be presented in 1980 census special reports on the 4merican Indian population.

Each American Indian reservation was assigned a unique 3-digit code by the Bureau. Enumeration districts (ED's) and block groups (BGs) which are inside boundaries of reservations are designated with an "N" in the ED prefix field in tape files.

Data summaries for American Indian reservations are included in STF's 2B, 2C, 4B, and 4C, and reports PC80-1-B and -C and HC80-1-A and -3.

Population and housing counts for reservations are scheduled to be included in a supplementary report (PC80-S1 series). Also, a population subject report (PC80-2 series) presenting additional data on American Indian reservations is also planned. Summaries on tape and in PC80-1-B and HC80-1-A show data not only for the reservation totals, but also for parts of reservations that cross State or county boundaries. Reservation data can also be derived from MARF, STF 1A, and STF 3A by the addition of component ED or BG summaries. Maps outlining reservation boundaries are included in the PC80-1-B and HC80-1-A reports. Reservation boundaries are also shown on detailed Metropolitan Map Series, place, and county maps.

Historical comparability
Data on 115 American Indian reservations were published in the 1970 census subject report, American Indians, PC(2)-1F. However, 1980 data may not be comparable to 1970 information because of boundary changes, improvements in geographic identification, new enumeration techniques, and other procedural changes made for the 1980 census.

American Indian Subreservation Areas
Entities known as "areas," "chapters," "districts," 'segments," or "communities," are associated with some American Indian reservations and were identified for the Census Bureau for the 1980 census by tribal governments or the Bureau of Indian Affairs. In a few cases, such subreservation areas extend beyond reservation boundaries or are located entirely outside the reservation (off-reservation). American Indian subreservations recognized for the 1980 census are identified by a unique 3-digit code.

Data for subreservations are not summarized in regular census tabulations; however, subreservation data can be obtained from the Census Bureau on a cost-reimbursable basis from special tabulations.

For further information regarding subreservation areas, please write Population Division, Racial Statistics Branch, Bureau of the Census, Washington, D.C. 20233.)

Historical comparability
American Indian subreservation areas were not identified separately in previous censuses.

American Indian Tribal Trust Lands
Some American Indian reservations have tribal trust lands in the vicinity of the reservation. The Bureau of Indian Affairs identified these areas for the 1980 census. Tribal trust lands are located outside the reservation boundary (off-reservation) and are associated with a specific reservation.

Population and housing counts for tribal trust lands are scheduled to be included in a supplementary freport (PC8041 series). Additional information for these areas may be included in special reports or unpublished tabulations. Also, such data can be obtained from the Census Bureau on a cost-reimbursable basis from special tabulations.

(For further information regarding the geography for tribal trust lands, please write to Population Division, Racial Statistics Branch, Bureau of the Census, Washington, D.C. 20233.)

Historical comparability
Tribal trust lands (off-reservation) were not identified in previous censuses.

Ancestry
A person's self-identified origin, descent, lineage, nationality group, or country in which the person or the person's parents or ancestors were born before their arrival in the United States. This item was asked on a sample basis.

This question was asked of persons regardless of how many generations their ancestors had been in this country. Persons were asked to write in the name of the group with which they most closely identify. Those who thought of themselves as having more than one origin were asked to write in their multiple ancestry, e.g., German-Irish. Instructions specified that religious groups were not to be reported as ancestry groups.

The open-ended write-in item on axes try was coded in census processing offices into a numeric representation using a code list containing over 400 categories. If a response was in terms of a dual ancestry, e.g., Irish-English, the person was assigned two codes, in this case one for Irish and one for English. Census basic record and public-use microdata files represent over 400 x 400 possible combinations. Selected three-ancestry combinations expected to be frequently reported were also coded, but, otherwise, whenever three or more ancestries are entered in a single response, only the first two were coded. Persons indicating two or more ancestries are shown in tabulations under "multiple ancestry" and may be counted more than once in tabulations of selected multiple-ancestry groups.

Most tabulations presenting counts of persons by ancestry show (a) the following single-ancestry groups: Dutch, English, French, German,
Greek, Hungarian, Irish, Italian, Norwegian. Polish, Portuguese,
Russian, (selected categories), Scottish, Swedish, Ukrainian, and other; (b) the number of persons reporting multiple ancestry, and the following selected multiple-ancestry groups: English and other group(s), French and other group(s), German and other group(s), Irish and other group(s), Italian and other group(s), and Polish and other group(s); and (c) ancestry not specified. Ancestry not specified includes nonresponses, also shown separately, as well as responses indicating religious groups, and unclassifiable responses. Only STF 4 presents more categories of ancestry than this at the State level or below.

Tabulations in STF 4 which present characteristics of specific ancestry groups at the State level or below present data for six single-ancestry groups--English, French, German, Irish, Italian, and Polish--and for four additional groups which vary from State to State. These four variable groups are the largest single- and/or multiple-ancestry groups in that State exclusive of (a) the six groups cited above, (b) all groups listed separately in the race and Spanish-origin questions, and (c) the category "American."

Historical comparability
The ancestry question, asked for the first time in 1980, in large part replaces a 1970 question on country of birth of parents, which together with the question on place of birth of the individual, identified the two generations comprising persons of foreign stock. There is no direct comparability between 1980 ancestry data (which refers to ancestry for an unlimited number of generations) and 1970 data on country of origin of persons of foreign stock.

See also: "Citizenship;" "Immigration, Year Of;" "Language Stoken At Home And Ability to Speak English;" "Nativity and Place of Birth".

Apartments
See "Units in Structure".

Armed Forces, Persons In
See "Labor Force Status".

Armed Forces Status
See "Labor Force Status".

Asian and Pacific Islander Population
See "Race".

Asking Price
See "Value".

Asking Rent
See "Rent, Contract".

Automobiles Available
The number of passenger cars available at home for the use of the members of the household, ascertained for occupied housing units. The term automobile includes station wagons, but excludes vans, pickups, or larger trucks. Cars rented or leased for one month or more, company cars, and police and government cars are also included if kept at home and used for nonbusiness purposes.

(Household members include lodgers or other nonrelatives living in the unit.) Dismantled or dilapidated cars or immobile cars used only as a source of power for some piece of machinery are excluded from this category. The statistics do not measure the number of automobiles privately owned or the number of households owning automobiles. This item was asked on a sample basis.

Limitations
A test survey taken before the census showed that the percent of households with three or more cars was understated.

Historical comparability
Similar data have been collected since 1960. Earlier counts, however, excluded taxicabs.

See also: "Transportation To Work, Means Of;" "Trucks Or Vans Available, Vehicles Available;" Vehicle Occupancy".

Barrio
See "Puerto Rico and Outlying Areas".

Bathrooms
The presence of bathroom facilities, ascertained for all occupied and vacant housing units. This question was asked on a sample basis.

Complete bathroom
A room with a flush toilet, bathtub or shower, and a wash basin with piped hot and cold water for the exclusive use of the occupants of the housing unit. (Although the instructions on the questionnaire do not specify that a complete bathroom must have hot water, this requirement was applied during the processing of the data in the edit combining the items on complete bathrooms and complete plumbing facilities for the exclusive use of the household.) The equipment must be inside the unit being enumerated.

No bathroom or only a half-bathroom
A unit with no bathroom facilities, only a half bathroom, or bathroom facilities which are also for the use of the occupants of other housing units. A half bathroom has at least a flush toilet or a bathtub or shower for exclusive use but not all the facilities for a complete bathroom.

Historical comparability
Data on number of bathrooms have been collected since 1960. The category "2 l/2 or 3 bathrooms" was included in 1970 but dropped for 1980.

See also: "Plumbing Facilities".

Bedrooms
The number of bedrooms, ascertained for occupied and vacant units. Bedrooms are rooms used mainly for sleeping, even if also used for other Purposes. Rooms reserved for sleeping such as guest rooms, even though used infrequently, are counted as bedrooms.

0n the other hand, rooms used mainly for other purposes, even though used also for sleeping, such as a living room with a sofa bed, are not considered bedrooms. A housing unit consisting of only one room, such as a one-room efficiency apartment, is classified, by definition, as having no bedroom. This item was asked on a sample basis.

Historical comparability
Similar data have been collected since 1960.

Birth, Place Of
See "Nativity and Place of Birth;" State Of Birth".

Black Population
See "Race".

Normally a rectangular piece of land, bounded by four streets. However, a block may also be irregular in shape or bounded by railroad, tracks, streams, or other features. Blocks do not cross the boundaries of counties, census tracts, or block numbering areas (BNA's). They may cross place boundaries and the boundaries of minor civil divisions (MCD's). When blocks cross place boundaries and, in 20 States (see figure 5, column 3), when they cross MCD boundaries, separate statistical summaries are presented for each part of the block.

Census blocks are normally compact units, but there are important exceptions. For example, in some suburbs, houses cluster around cul-de-sacs. In these areas a census block may be fairly large since only those features that serve as the perimeter of an enclosed area are treated as block boundaries. Also, in those rural areas where they are numbered, blocks may include many square miles, depending on the frequency of intersections of roads, rivers, mountain ridges, or other physical features.



Census data are tabulated by block in all urbanized areas (UA's) and generally for some territory extending beyond the UA boundaries. Data also are tabulated by block in incorporated places with 10,000 or more inhabitants outside UA's, and in other areas which contracted with the Census Bureau for the preparation of block statistics. Places outside of UA's are included in the block statistics program if they met the 10,000 population criterion in the 1970 census, in official Bureau estimates through 1976, or in a special census taken on or before December 31, 1977. Block coverage for qualifying places is within boundaries as of January 1, 1980. Five States contracted for the preparation of block statistics for all of their territory, both urban and rural, not already in the block statistics program. These States are Georgia, Mississippi, New York, Rhode Island, and Virginia.

A block is identified by a 3-digit code which is unique within census tract or, where tracts do not exist, BNA. Since separate summaries are provided for the parts of a block split by a place boundary or, in 20 States, an MCD boundary, tape users often will need to specify the place or MCD code, along with other codes, to retrieve data for a block. Blocks are defined on detailed census maps: Metropolitan Map Series (MMS), Vicinity Map Series (VMS), place and county maps. The extent of block statistics coverage is reflected on maps by the presence of the 3-digit block number and the absence of ED boundaries and numbers.

On census maps, when a block boundary ignores a minor physical feature, such as a railroad track, a "fishhook" across the feature indicates that the block includes area on both sides of the feature. Alternatively, the separate parts of such a block may have identical block numbers, each followed by an asterisk.

The maps used for enumeration activities were, of necessity, obtained several years prior to the census and therefore do not reflect recently constructed streets. Only those features shown on the maps can serve as block boundaries.

Statistics were collected for approximately 2.6 million blocks in the 1980 census. Block statistics are included in PHC80-1 Block Statistics microfiche series and in file B of Summary Tape File 1 (STF 1B).

Historical comparability
In 1970, block statistics were prepared for UA's (and some territory beyond) located in SMSA's existing at the time of the census, as well as for contract areas. Unlike 1980, they were not prepared for places of 10,000 population or more outside UA's unless done under contract, nor for UA's in not-yet-defined SMSA's.

Some blocks defined for 1970 will have new boundaries in 1980, primarily those on the edges of UAs and other areas of new development where the street patterns have changed. To help the user notice a change wherever a block has been redefined by splitting or other adjustment, the 1970 block number wi11 generally not be reused. Where blocks were recognized for the 1970 census, their boundaries and numbers generally will be the same in 1980, except for a few areas where blocks were renumbered by local GBF/DME-File coordinating agencies in order to define more desirable block groups.

Block Group (BG)
A combination of numbered census blocks that is a subdivision of a census tract or block numbering area (BNA) and is defined in all areas for which block statistics are prepared. (In areas where blocks are not numbered, ED's are used instead of BG's.)

BG's are not outlined on census maps, but are defined as that set of numbered blocks sharing the same first digit within a census tract or BNA. For example, Block Group "3" within a particular census tract would include any blocks numbered between 301 and 399. In most cases, the numbering would involve substantially fewer than 50 blocks, since gaps are occasionally left in the numbering; e.g. Block 312 might be followed by Block 316.

BG's are defined within census tract or BNA. They may cross, and be split by, the boundaries of minor civil divisions (MCD's) or census county divisions (CCD's), places, congressional districts, urbanized areas, and Indian reservations. When this occurs, statistical summaries (data records) are provided for each component or part. To avoid mistaking a component summary for a complete BG summary, users should carefully study census maps to note any BG's split by place, MCD or CCD, urbanized area, or Indian reservation boundaries. Congressional district (CD) boundaries are not shown on census maps, so the maps will not be of use in detecting BGs split by CD boundaries.

BG summaries observe boundaries of some areas (specifically, CCD's and, in 10 States, MCD's) which are ignored in summarizing data for the block statistics presentations in reports and on tape. As a result, it occasionally will be necessary to add BG components together to match the sum of blocks in the same hundreds series.

Statistics will he prepared for almost 200,000 BGs. 3G data, together with data for ED's, appear on STF's 1A and 3A, and in any corresponding microfiche. There are no printed data for BG's.

Historical comparability
In areas where BG's were tabulated in,
1970, many 1980 BG's will be the same as their 1970 counterparts, with exceptions occurring primarily in areas where tract boundaries have changed or where substantial development has taken place. Also, BG parts, created when BG's are split by the boundaries of higher level areas, will change if such boundaries have changed.

Many areas with BG's in 1980 had data reported by ED's in 1970, a change occasioned in part by the expansion of the block statistics program, and in part because ED's were used for tabulation purposes in 1970 instead of BG's in some block-numbered areas. Where BGs have replaced ED's, there will be little comparability between 1970 ED's and 1980 BG's.

Block Numbering Area (BNA)
An area defined for the purpose of grouping and numbering blocks in block-numbered areas where census tracts have not been defined--typically, in nonSMSA places of 10,000 or more population and in contract block areas. BNA's do not cross county boundaries. They are identified by census tract-type numbers ranging from 9901.00 to 9989.99 which are unique within a county. While BNA numbers are similar to census tract numbers, BNA's are not census tracts and are not included in STF's 2 or 4.

BNAs maybe split by the boundaries of places, MCD's, and CCD's.

Statistical summaries appear in STF 1B and PHC80-1 Block Statistics microfiche series for the component parts of BNA's created when BNA's are split by the boundaries of places and, in 20 States, MCD's. (See figure 5, column 3.) Such component summaries appear in STF 1A and 3A when BNA's are split by the boundaries of CCD's in 20 States (see figure 5, column 1), and MCD's in 10 other States and Puerto Rico.

Historical comparability
While BNA's were also used in previous censuses, any historical comparability is generally coincidental.

Boarded-Up Status
Determined for vacant units intended for year-round use. Boarded-up units have windows and doors covered by wood, metal, or similar materials to protect the interior and prevent entry. A single-unit structure or a unit(s) in a multi-unit structure may be boarded-up in this way. This item was ascertained on a complete-count basis.

Historical comparability
This item is new for 1980.

Boarder
See "Household Relationship".

Borough (In Alaska)
See "County".

Business, Type Of
See "Industry".

Car Commuting
See "Transportation to Work, Means Of".

Carpooling
See "Transportation to Work, Means Of;" "Vehicle Occupancy".

Cars Available
See "Automobiles Available".

Census Area (In Alaska)
See "County".

Census County Division (CCD)
A statistical subdivision of a county, roughly comparable to a minor civil division (MCD). CCD's are defined in 20 States (see figure 5, column 1) which do not have MCD's suitable for reporting census statistics (i.e., the MCD's have lost their original significance, are very small in population, have frequent boundary changes, and/or have indefinite boundaries). CCD'S are established cooperatively by the Census Bureau and both State and local government authorities. They are generally defined by boundary features that seldom change and can be easily located, such as roads, rivers, and powerlines.

CCD boundaries are represented on detailed census maps, such as MMS/VMS sheets and county maps. In addition, CCD outlines appear at a small scale on maps published in several 1980 reports. CCD's in alphabetic sequence are assigned unique, incremental 3-digit numeric codes within counties.

Statistics for about 5,500 CCD's appear in STF's 1A, 2B, 3A, and (under tentative plans) 4B, and in PC80-1-A and -B and HC80-1-A reports.

Historical comparability
In 1980, CCD's are defined in one fewer State than in 1970--North Dakota returned to the use of its MCD's (townships). In the past, cities with 10,000 or more inhabitants generally were defined as separate CCD's. When these cities annexed territory, CCD boundaries also had to be adjusted. For 1980, many of these CCD boundaries were revised to conform with census tract boundaries where tracts exist, and permanent physics1 features elsewhere, in an attempt to minimize future CCD boundary adjustments. CCD's which changed boundaries between 1970 and 1980 are noted in footnotes to table 4 of the PC80-1-A reports for States with CCD's.

Census Subarea
A statistical subdivision of a "census area" or borough (county equivalent) in Alaska. Census subareas take the place of minor civil divisions (MCD's) or census county divisions (CCD's).

Historical comparability
In 1970, Alaska county equivalents were called "divisions," and some were subdivided further. Some of the census subareas used in the 1980 census approximate the 1970 divisions or their subdivisions.

Census Tract
A small statistical subdivision of a county. Tracts generally have stable boundaries. When census tracts are established, they are designed to be relatively homogeneous areas with respect to population characteristics, economic status, and living conditions. Tracts generally have between 2,500 an3 8,000 residents. All standard metropolitan statistical areas (SMSA's) recognized for the 1980 census have census tracts. Most of these SMSA's are completely tracted, but seven SMSA's newly created as a result of the 1980 census include outlying counties which are not tracted. In addition, an estimated 3,000 census tracts have been established in 221 counties outside SMSA's. Five States and the District of Columbia are entirely tracted: Connecticut, Delaware, Hawaii, New Jersey, and Rhode Island. In all, there are over 43,300 census tracts for the 1980 census (including 465 in Puerto Rico).

Census tract boundaries are established cooperatively by local Census Statistical Areas Committees and the Census Bureau in accordance with guidelines that impose limitations on population size and specify the need for visible boundaries. Geographic shape and area size of tracts are of relatively minor importance. Tract boundaries are established with the intention of being maintained over a long time so that statistical comparisons can be made from census to census. Census tracts observe county lines and cover all of the territory within each tracted county. Within a county, tract boundaries may be split by other geographic boundaries.

Census tracts are identified by a 4-digit basic code and may have a 2-digit suffix, e.g., 6059.02. On tape, the decimal is implied.

Many census tracts do not have a suffix. In such cases, tapes give the 4-digit code followed by two blanks. Leading zeros in a tract number (e.g., 0025.02) do not appear on the maps (e.g., 25.02).

Tract numbers are always unique within a county and, except for the New York SMSA, are also unique within an SMSA. All valid census tract numbers are in the range 0001 to 9899.99; a number between 9901 and 9989.99 denotes a block numbering area (BNA).

Census tract boundaries are shown on all detailed census maps, such as place and county maps. In addition, census tract outline maps are being created for each SMSA and each tracted county outside SMSA's. Tract outline maps show only those streets and physical features which serve as census tract boundaries. In addition, the boundaries of places, MCD's, CCD's, counties, and States appear on tract outline maps.

Census tract data are presented in STF's 1A, 1B, 2A, 3A, and 4A, and in PHC80-2 Census Tracts reports. In STF 1A and 3A, tract data are presented in hierarchical sequence within place within MCD or CCD. In a case where a tract is split by place, MCD, or CCD boundaries, the tape files will have summaries for each of its parts. To get data for the whole tract, it will be necessary to add up the components. In STF 1B the situation is similar except that MCD boundaries are observed in only 20 States and Puerto Rico. (See figure 5, column 3.) MCD boundaries in the other 10 States with MCD'S and CCD boundaries in the remaining 20 States are ignored. In the major summaries for census tracts--those in STF 2A and 4A and in PXC80-2 Census Tracts reports--tract summaries observe the boundaries of places of 10,000 or more population. Separate summaries provide totals for split tracts.

Historical comparability
Census tracts are defined with an overall goal of census-to-census comparability. Some 1970 tracts have been subdivided due to increased population, but the new tracts can be recombined by the user for comparison with 1970 tracts. This affects about 8 percent of all 1970 tracts. Other changes have included combinations of two or more small 1970 tracts (less than 1 percent of all 1970 tracts) and adjustments to tracts boundaries where old boundary features have disappeared or better boundaries (e.g., freeways) have come into being. In a few areas, local Census Statistical Areas Committees undertook extensive redefinition of census tracts.

Census Tracts reports, PHC80-2, include 1970-1980 tract comparability tables. 1980 tracts which were split, combined, or had boundary realignments affecting areas with 100 or more people are listed, along with the 1970 tracts or parts of tracts to which they correspond. The list is presented both ways: 1970 tracts in terms of 1980 counterparts, and 1980 tracts in terms of 1970 counterparts. Since the affected parts of individual tracts (e.g., individual blocks) are not specified, the comparability list essentially serves to draw attention to areas which should be studied further on 1980 and 1970 maps, preferably those which show detail by block.

Both the number of tracted counties and the number of census tracts increased by over 20 percent between 1970 and 1980. The reporting of data for split tracts has also increased. Whereas 1970 Census Tracts reports gave data for tract parts created when tracts were split by the boundaries of only those places with 25,000 or more population, 1980 reports observe boundaries of places as small as 10,000. 1980 STF's 2 and 4 present data for the components of split tracts, as well as for whole tracts, whereas their 1970 counterparts did not provide separate summaries for the components of split tracts.

Central Business District (CBD)
An area of high land valuation characterized by a high concentration of retail businesses, service businesses, offices, theaters, and hotels, and by a high traffic flour. A CBD follows census tract boundaries, i.e., it consists of one or more whole census tracts. CBO's are identified only in central cities of SMSA's and other cities with a population of 50,000 or more, and are designated by local Census Statistical Areas Committees in consultation with the Census Bureau. However, some eligible cities have chosen not to participate in the CBD delineation program. CBD's generally do not extend beyond the boundaries of the city.

The CBD's now recognized were delineated for the 1977 economic censuses. The Bureau does not plan to prepare 1980 statistics for CBD's, but users may derive data by aggregating data for component census tracts or smaller areas. Records for such areas in the Geographic Identification Code Scheme report and on machine-readable 1980 files include a CBD code when the area is in a CBD.

Historical comparability
At the time of the 1970 census, CBD's were defined only in cites of 100,000 or more persons.

Central City
See "Standard Metropolitan Statistical Area;" "Urbanized Area".

Children
See "Household Relationship".

Children Ever Born
Total live births born to women 15 years old and over regardless of marital status. Respondents were instructed to include children born to the woman before her present marriage, children no longer living, children born to the woman who were still living in the home, as well as children away from home. This item was asked on a sample basis.

Typical presentations include categories for 10-year age groups: 15 to 24, 25 to 34, 35 to 44, and separately for ever-married women as well as for women regardless of marital status in the age group. Data are most frequently presented in terms of the aggregate number of children ever born to women in the specified category and in terms of the rate per 1000 women. For purposes of calculating the aggregate, the open-ended response category "12 or more" is assigned 1 value of 13.

Limitations
These data are assumed to be less complete for illegitimate than for legitimate births. An evaluation study after the 1970 census found that the census overstated the number of women with no children ever born, relative to the results of reinterviews, that is, more women had had children than 1970 census data indicated.

Historical comparability
A similar question has been asked in each census since 1890 except those in 1920 and 1930; however, prior to 1970 the question was restricted to women who had ever been married. Most tabulations in 1970 were restricted to ever-married women.

Civilian Labor Force
See "Labor Force Status".

Class of Worker
Classification of workers according to the type of ownership of the employing organization. Class of worker is generally tabulated for employed persons 16 years old and over, but it is also obtained for 15-year-olds and persons not currently employed who have worked since 1975, in which case the data refer to the person's most recent employer or business. The determination of class of worker is independent of occupation and industry classifications, but refers to the same job. These data were collected on a sample basis.

Private wage and salary workers
Employees of a private company, business, or individual who work for wages, salary, commissions, tips, or payment in kind. Work for wages or salary from settlement houses, churches, unions, and other nonprofit organizations is also included, as are those self-employed persons whose business is incorporated.

Employee of own corporation
Persons who own all or most of the stock in a privately held corporation and often consider themselves to be self employed. In fact, they are classified as private wage and salary workers.

Government workers
Persons who work for any governmental unit regardless of the activity of the particular agency. Employees of public schools, government-owned bus lines, government-owned electric power utilities, etc. are included, but employees of private organizations which do contract work for government agencies are not included. Government workers include persons elected to paid offices. Persons on active duty in the Armed Forces are assigned a Federal government class of worker code in the computer editing operation; however, the Bureau's class-of-worker tabulations are limited to civilians. The government workers category is subdivided by the level of government: Federal government workers, State government workers., and local government workers.

In some states, teachers in elementary and secondary schools, who are in fact local government workers, tend to report themselves as State government workers. The result is likely to be an overstatement of the number of State government workers.

Self-employed workers
Persons who work for profit or fees in their own unincorporated business, profession, or trade, or who operate a farm. Included here are the owner-operators of large stores and manufacturing establishments as well as small merchants, independent craftspersons and professionals, farmers, peddlers, and other persons who conduct enterprises on their own. Persons whose own business is incorporated are counted as employees of their corporation and are tabulated in the "private wage and salary workers" category.

Unpaid family workers
Persons who work without say on a farm or in a business operated by a person to whom they are related by blood or marriage. These are usually the children or the spouse of the owner of a business or farm. About one-half of the unpaid family workers are farm laborers. Unpaid family workers, who reported working fewer than 15 hours during the reference week were not considered to be "at work" in the determination of labor force status.

Historical comparability
Class-of-worker data have been collected since 1940. Level of government and "employee of own corporation" were not collected as separate categories before 1970. Since persons who reported being employees of their own corporations were counted in 1970 and 1980 as private wage and salary workers, there is probably an overstatement of the self-employed category in figures for 1940 to 1960. 1970 and 1980 data are comparable.

College Attendance
See "School Level;" "School Years Completed".

College Dormitories
See "Group Quarters Type".

College Graduate
See "School Years Completed".

College Teachers
See "Occupation".

Commercial Establishment or Medical Office
See "Owner Costs, Selected Monthly;" "Value".

Commuting
See "Vehicle Occupancy;" "Transportation to Work, Means Of".

Complete Kitchen Facilities
See "Kitchen Facilities, Complete".

Condition of Housing
See "Plumbing Facilities".

Condominium Status
A type of ownership of an apartment in a building--or a house in a development--where ownership of common areas is shared. This item was asked on a complete-count basis.

Condominium
Ownership that enables a person to own an apartment or house in a development of similar units and hold a common or joint-ownership in common areas, hallways, entrances, elevators, etc. The owner has a deed to the individual unit, and, very likely, a mortgage on the unit, and also holds a common or joint ownership in all common areas, such as grounds, lobbies, and elevators. A condominium unit need not be occupied by the owner to be counted as such.

Noncondominium
All other types of ownership, including cooperative where a share in a corporation with title to a multiunit property entitles the owner to occupy a specific unit.

Limitations
In a test survey taken before the census, an overstatement of condominiums was noted. Therefore, an edit was introduced in the 1980 census voiding apparently spurious condominium responses in blocks or enumeration districts with a very small number of such responses on the assumption that condominium units can occur only in groups of several condominium units.

Historical comparability
In 1970, owner-occupied cooperative and condominium housing units were identified together. In 1980, only condominium units are identified. The 1980 data also include vacant and renter-occupied condominium housing units, not just owner occupied condominium housing units as in 1970.

Congressional District
One of the 435 State or sub-State areas from which persons are elected to the U.S. House of Representatives. Two sets of congressional districts are recognized in 1980 census products. Districts of the 97th Congress (1981-1982) are summarized on STF 1A and STF 3A. Districts of the 98th Congress (1983-1984) reflecting redistricting based on the 1980 census, are summarized on STF 1D and STF 3D and in series PHC80-4, Congressional Districts of the 98th Congress.

The PHC80-4 reports, issued by State, include a map of the State showing congressional district boundaries in relation to county outlines. More detailed maps follow showing selected congressional district boundaries in cases where the State map cannot delineate the congressional districts with sufficient clarity. These maps will be republished later in the Congressional District Atlas for the 98th Congress. Congressional district boundaries are not shown on detailed 1980 census maps.

Historical comparability
Districts of the 97th Congress were the same as districts for the 93rd Congress for all but 4 States: New York, California, and Texas, which were redistricted for the 94th Congress; and Tennessee, in which one boundary change took effect for the 95th Congress. 1970 data for these congressional districts were published in Congressional District Data (CDD) report series for the 93rd and 94th Congresses, but not including the later change for Tennessee. The Congressional District Data Book republished CDD reports for the 93rd Congress.

Contract Rent
See "Rent, Contract".

Cooking Facilities
See "Kitchen Facilities, Complete".

Cooking Fuel
See "Fuel".

Correctional Institutions
See "Group Quarters Type".

See" Energy Costs, Monthly Residential;" "Owner Costs, Selected Monthly;" "Rent, Contract;" "Rent, Gross".

Country of Birth
Foreign-born persons were asked to report their country of birth. Persons born in Puerto Rico, in an outlying area of the United States (e.g., Guam), or abroad of American parents (determined in the question on citizenship) are native and therefore are excluded from country-of-birth tabulations. These data come from the place-of-birth question, which also collected information on State of birth for natives, and was asked on a sample basis.

Foreign-born persons were asked to report their country of birth according to international boundaries as recognized by the U.S. government as of April 1, 1980. The respondent's entry was manually coded in census processing offices into a classification system consisting of over 250 foreign countries or groups of countries, as well as 22 categories for outlying areas of the United States. Most data presentations include 20 to 60 foreign-country categories. Census basic records and public-use microdata files separately identify 300 countries of birth.

Historical comparability
A similar question on country of birth was asked in 1970.

See also: "Nativity and Place of Birth;" "State of Birth".

Country of Residence In 1975
See "Residence In 1975".

County
The primary political and administrative subdivision of a State. In Louisiana, such divisions are called parishes. In Alaska 23 boroughs and "census areas" are treated as county equivalents for census purposes. Several cities (Baltimore, Maryland; St. Louis, Missouri; Carson city, Nevada; and 41 Virginia cities) are independent of any county organization, and thereby constitute primary divisions of their States and are treated the same as counties in census tabulations.

County boundaries are shown on most census maps. A 3-digit Federal Information Processing Standards (FIPS) county code identifies each county uniquely within State. Counties are numbered in alphabetic sequence, with independent cities numbered separately at the end of the list.

There are 3,215 counties, and county equivalents (including 78 in Puerto Rico) recognized for the 1980 census. Tabulations for all counties appear in STF's 1 through 4, and in PC80-1-A, -B, and -C, HC80-1-A and -B, and PHC80-3 reports. Tabulations for counties of 30,000 or more inhabitants appear in STF 5.

Historical comparability
A number of changes have occurred to county boundaries since 1970. A new set of county equivalents (boroughs and census areas) has been defined for Alaska, and in some cases these county equivalents differ considerably from the census divisions recognized for 1970. In addition, there are minor changes in counties for South Dakota and Hawaii. In Virginia, county boundaries have changed as a result of the creation of new independent cities and annexations by independent cities. Most other changes represent minor adjustments of the boundaries between counties. Those counties which changed boundaries between 1970 and 1980 are noted in footnotes at the end of table 4 of the PC80-1-A report for each State.

County Equivalent
See "County".

County Subdivision
See "Census County Division;" "Census Subarea;" "Minor Civil Division".

Crop Sales
See "Farm Residence".

Crowding
See "Persons Per Room".

Direct Access
See "Housing Unit"

Disability
Presence of a physical, mental, or other health condition which has lasted 6 or more months and which limits or prevents a particular type of activity. Two types of disability were cited on the questionnaire--work disability, which is tabulated for noninstitutional persons 16 to 64 years old; and public transportation disability, which is tabulated for noninstitutional persons 16 to 54 years old and for noninstitutional persons 65 years old and over. This item was asked on a sample basis.

The term "health condition" refers to any physical or mental problem which has lasted for 6 months or more. A serious problem with seeing, hearing, or speech would be considered a health condition, whereas pregnancy or a temporary health problem such as a broken bone that is expected to heal normally would not be considered a health condition.

Categories of work disability status
With a work disability
Persons who have a health condition which limits the kind or amount of work or prevents working at a job or business. A person is limited in the kind of work he or she can do if the person has a health condition which restricts his or her choice of jobs. A person is limited in amount of work if he or she is not able to work at a full time (35 or more hours per week) job, or business. Within this category, tabulations are frequently provided on the number of persons with a work disability who are not in the labor force.

Prevented from working
Persons not in the labor force who have a health condition which prevents working at any job or business.

Public transportation disability category
With a public transportation disability
Persons who have a health condition which makes it difficult or impossible to use buses, trains, subways, or other forms of public transportation.

Limitations
The disability item was included in the 1980 census because of the need for local area data on the relative prevalence of work and public transportation disabled persons. The decision to include the item was made even though there was test evidence that there was likely to be a problem with data reliability. Specifically, an analysis of the 1976 National Content Test, which collected disability information in both an original interview and a subsequent reinterview, showed that the indexes of inconsistency for responses to the work and public transportation disability questions were in the moderate to high range.

Historical comparability
The 1970 disability item was concerned only with work disability and did not attempt to identify persons with a public transportation disability. The 1970 item did not contain a clause restricting disability to those resulting from a health condition which had lasted 6 or more months; however, it did contain a separate question about the duration of the disability.

Division (Census Geographic)
A census geographic division is one of the nine groups of States which are subdivisions of the four census geographic regions of the United States. (See figure 6.) Census geographic divisions are identified by a 1-digit code which is also the first digit of the 2-digit census geographic code for each State in the division.

Historical comparability
Census divisions have remained unchanged since the 1910 census, except for the expansion of the Pacific division to include Alaska and Hawaii.

Divorce
See "Marital Status".

Duration of Vacancy
See "Vacancy, Duration Of".

Earnings
See "Income Type".

Economic Subregion (ESR)
A grouping of State economic areas (SEA's) which brings together those SEA's which are most closely related in terms of their economic and social characteristics. The areas were first defined following the 1950 census and updated after the 1960 census. In order to achieve such homogeneity, State boundaries are frequently crossed. The 510 SEA's are grouped into 121 ESR's. A 3-digit numeric code is assigned to each ESR. No data summaries will be prepared for ESR's, although the ESR code appears on the geographic records of the summary tape files.



Historical comparability
ESR boundaries have remained the same since 1960.

Elderly, Homes For
See "Group Quarters Type".

Election Precinct
In census usage, any of a variety of types of areas (e.g., election districts, precincts, legislative districts, wards) defined by States and local governments for purposes of elections. Under a cooperative Census Bureau/State program, the boundaries of election precincts and ED's or census blocks were drawn so as to be compatible in many States.

The Bureau prepared election precinct data for all or portions of 23 States; in some other States, users may aggregate block data to create election precinct statistics. The election precinct data appear in the P.L. 94-171 Population Counts tape file and on microfiche of that file.

Historical comparability
Election precincts have not been recognized in past censuses, except where they have served as minor civil division boundaries.

Electricity
See "Energy Costs, Monthly Residential;" "Fuel".

Elementary School Enrollment
See "School Level".

Elevator, Passenger
Presence of a passenger elevator in the structure, ascertained for occupied and vacant housing units in structures with four or more stories or floors. Elevators are counted even if used largely, though not exclusively, for freight. Also included are stairway elevators and wheelchair lifts installed in structure of four or more stories. This item was asked on a sample basis.

No elevator
The number of housing units in structures with four or more stories with no passenger elevator or with only elevator service used for freight.

Historical Comparability
Similar data were collected in 1960 and 1970; in 1960, however, these data were collected only in cities with 50,000 or more persons.

See also: "Stories In Structure".

Employment Status
See "Labor Force Status".

Employment, Type Of
See "Class of Worker".

Energy Consumption
See "Air Conditioning;" "Energy Costs, Monthly Residential;" "Fuel;" "Heating Equipment".

Energy Costs, Monthly Residential
The average monthly expense for fuels and utilities in occupied housing units. Fuels include oil, coal, wood, kerosene, and other fuels; utilities include electricity, gas, and water. Costs are recorded if paid by or billed to occupants, a welfare agency, relatives, or friends. Costs paid by landlords or included in condominium or cooperative fees are excluded. Also excluded are payments by occupants for fuel bills other than their own. Water and fuel costs are converted from a yearly basis as reported, to a monthly basis.

Utility and fuel costs are used primarily as components of "Gross Rent" and "Selected Monthly Owner Costs." since utilities included in rent payments are not recorded, residential energy cost data for renter-occupied units are of limited value for direct study. For that reason, separate fuel and utility cost figures are not issued in the more widely circulated census reports, but only on summary tapes. Basic record tapes and microdata show dollar amounts up to $999 for electricity, gas, and water, and to $9,999 for fuels. If the respondent used words or symbols such as more than" or some dollar amount with a "+", a dollar was added to the amount; if "less than" was used a dollar was subtracted. If the entry read "around," "approximately," or "about," the amount reported was used. These items were asked on a sample basis.

Monthly residential energy costs as percentage of income
Monthly residential energy costs divided by one-twelfth of the household income in 1979.

Limitations
A sample taken before the census showed that respondent's estimates were overstated as compared with utility company records.

Historical comparability
Similar data were collected for renters only in 1960 and 1970. Directions implied in the 1970 format were made explicit to respondents in 1980: "The amounts to be reported should be for the last 12 months, that is, for electricity and gas, the monthly average for the past 12 months; for water and other fuels, the total amount for the last 12 months." The expression "included in rent" was expanded to "included in rent or no charge."

See also: "Fuel;" "Owner Costs, Selected Monthly;" "Rent, Gross".

English Speaking Ability
See "Language Spoken At Home and Ability To Speak English".

Enrollment in School
See "School Enrollment".

Enumeration District (ED)
An area used in the 1980 census for (data collection activities and as a tabulation area where blocks are not present. ED's do not cross the boundaries of legal or statistical areas; for example, census tracts, MCD's/CCD's, places, counties, congressional districts, and States. Because of these constraints, they vary widely in population size, although they do not generally exceed a population of 1,600 in areas where the census was taken by mail, or a population of 1,000 in areas where the census was taken by conventional enumerator canvassing. The population limits are designed so that an ED generally represents a reasonable workload for one enumerator. About 1,000 jurisdictions in 47 States participated in a program for local definition of ED's. In areas without blocks, ED's are the smallest unit of census geography for which statistics are prepared.

ED boundaries are shown on MMS/VMS, place, and county maps in areas where there are no block numbers. ED's are identified by a 4-digit number (except that leading zeros, when they occur in ED numbers, do not appear on the maps). An ED number may be followed by a 1-letter alphabetic suffix. The suffix is used to identify subdivisions of ED's made during data collection and processing activities where the original ED proved to be too populous for an efficient work unit, or to accommodate a revision to a place or other boundary made after January 1, 1978 in mail-out/mail-back areas or January 1, 1979 in conventional census areas. An ED number may also have a l-letter prefix indicating that the ED is of a special type (e.g., an American Indian reservation), but the prefix is not necessary for unique identification of the ED. ED numbers do not repeat within a county. Any ED may be uniquely identified by accompanying its ED code with the 2-digit State code and 3-digit county code.

Statistics will be prepared for about 100,000 ED's. ED data, together with data for BG's, appear on STF's 1A and 3A and corresponding microfiche. In addition, ED data appear on STF 1B to complement the summaries for blocks. There are no printed data for ED's.

Historical Comparability
Many areas which were covered by ED's in 1970 are summarized in terms of blocks and BG's for 1980. In some cases it may be possible to add up blocks to approximate the 1970 ED'S, based on detailed comparison of 1980 and 1970 maps.

In areas covered by ED's for 1980, enumeration considerations dictated ED size and design, and historical comparability does not normally enter into consideration.

Equipment
See "Air Conditioning;" "Heating Equipment;" "Telephone In Housing Unit;" "Vehicles Available".

Eskimo Population
See "Race".

Ethnicity
See "Ancestry;" "Language Spoken At Home and Ability to Speak English;" "Nativity and Place of Birth;" "Race;" "Spanish Origin".

Experienced Civilian Labor Force
See "Labor Force Status".

Extended City
See "Urbanized Area".

Family
Two or more persons, including the householder, who are related by birth, marriage, or adoption, and who live together as one household; all such persons are considered as members of one family.

(Persons not in families and not inmates of institutions are classified as unrelated individuals.) Families are defined using responses to the complete-count household relationship question.

If the son/daughter of the person or couple who maintains the household and the son's or daughter's spouse and /or children are members of the household, they are treated as part of the householder's family. 1 roomer/boarder and his/her spouse who are not related to the person or persons who maintain the household, or a resident employee and his/her spouse living in are not counted as a family, but as individuals unrelated to the householder. Thus, a household can contain only one family for purposes of census tabulations.

A person maintaining a household alone, or two or more unrelated persons are regarded as a household but not as a family. Thus, some households do not contain a family.

Subfamily
A married couple with or without own children, or one parent with one or more own children (parent-child group), living in a housing unit and related to the householder, but excluding the householder (for example, a young married couple sharing the home of the husband's or wife's parents). Since subfamily members are counted as part of the householder's family, the number of subfamilies is not included in the count of families per se. Subfamilies are defined during processing of sample data. In selected tabulations, subfamilies are further classified by type: married-couple subfamilies, with or without own children; father-child subfamilies; and mother-child subfamilies.

(In certain Census Bureau surveys (e.g. CPS) before 1980, families as defined here are referred to as "primary families." The term "secondary family" refers to a resident family unrelated to the householder, such as a roomer and his or her spouse. Tabulations of families from such surveys include secondary families.)

Historical comparability
A similar definition for family was used in 1970. In 1960, secondary families were also identified.

See also: "Household Relationship;" "Unrelated Individual".

Family Income In 1979
Total money income received in calendar year 1979 by all family members 15 years old and over, tabulated for all families. Family income differs from household income by excluding income received by household members not related to the householder, persons living alone, and others in nonfamily households. (Income of these unrelated persons along with income of persons living in noninstitutional group quarters is tabulated as income of unrelated individuals 15 years old and over.) See the definitions of "Income In 1979" and "Income Type" for a discussion of the sources of income recorded, means, medians, limitations, and comparability.

In income tables for families, the lowest income group (e.g., less than $2,500) includes families that were classified as having no 1979 income as defined in the census. Many of these were living on income "in kind," savings, or gifts; were newly created families: or were families in which the sole breadwinner had recently died or left the household. However, many of the families who reported no income probably had some money income which was not recorded in the census. Family income is recorded on public-use microdata in $10 intervals up to $75,000 or down to a net loss of $9,990 or more.

Median and mean family income figures are based on all families, unlike mean or median income figures for persons 15 years old and over, which exclude persons with no income. This item was derived on a sample basis.
Historical comparability: Family income distributions have been tabulated in each census since 1950. Family income has been replaced by household income distributions in certain tabulations for 1980.

See also: "Income In 1979".

Family Members
See "Household Relationship".

Family Type
Families are classified by type according to sex of the householder and the presence of relatives, based on questions on sex and household relationship asked on a complete-count basis.

Married-couple family
A family in which the householder and his/her spouse are enumerated as members of the same household.

Other family
Male householder, no wife present
A family with a male householder and no spouse of householder present.

Female householder, no husband Present
Family with a female householder and no spouse of householder present.

Historical comparability
The terminology for the family-type categories is new for 1980. The categories are reasonably compatible with the 1970 categories, "husband-wife families," "families with other male head," and "families with female head."

See also: "Family;" "Household Type".

Farm Residence
Presence of persons or housing units on farms. A farm is a place with $1,000 or more in sales of crops, livestock, or other farm products during the preceding calendar year. Farm residence is determined for both occupied and vacant housing units in rural areas. The question was structured to exclude units on city or suburban lots or on places of less than one acre. Urban areas are excluded through editing. Data are summarized in terms of housing units on farms or persons living on farms--not the number of farms. This item was determined on a sample basis.

Rural Farm
In a rural area and on a place with $1,000 or more in sales of crops, livestock, or other farm products during the preceding calendar year.

Rural Nonfarm
In a rural area but not on a farm as defined above. This need not imply location in a sparsely settled area, since "rural" includes incorporated and unincorporated places with fewer than 2,500 inhabitants outside urbanized areas.

Historical comparability
Farms have been counted since 1593; farm and nonfarm residence, since 1930. Before 1960, farm residence was determined essentially by self-identification; i.e., respondents answered whether they lived on a farm. Determination of farm residence based on acreage and sales of farm products began in 1960. In 1970, a farm was defined as a place in rural territory with at least $250 in sales of farm products, plus additional places with 10 or more acres and $50 or more in sales of farm products. The information on acreage in item H15 is included to allow comparable tabulations to be developed for both old and new farm definitions.

Farm Self-Employment Income
See "Income Type".

Farm Workers
See "Industry;" "Occupation".

Federal Government Employees
See "Class of Worker".

Females
See "Family Type;" "Sex".

Fertility
See "Children Ever Born".

Financial Characteristics
See "Owner Costs, Selected Monthly;" "Rent, Contract;" "Rent, Gross;" "Value".

Fire and Hazard Insurance
See "Owner Costs, Selected Monthly".

Foreign-Born Persons
See "Nativity and Place of Birth".

The types of combustible matter most often used for house heating, water heating, and cooking in occupied housing, units, tabulated separately. The term "house heating" applies to all types of structures, including apartment buildings. These items were asked on a sample basis.

Utility gas
Gas piped underground from a central system (public utility company, municipal government, or the like) that serves the neighborhood.

Bottled, tank, or LP gas
Bottled, tank, or liquefied petroleum gas stored in tanks which are refilled or exchanged when empty.

Electricity
Fuel oil, kerosene, etc
Fuel oil, distillate, residual oil, kerosene, gasoline, alcohol, and other combustible liquids and semi-fluids.

Coal or coke
Purchased wood, wood cut by household members on their property or elsewhere, driftwood, sawmill or construction scraps, or the like.

Other fuel
All other fuels not specified elsewhere, including purchased steam, fuel briquettes, coal dust, waste materials such as corncobs, etc. Households that use solar energy as the prime source of fuel are also included in this category. In certain tabulations of limited detail, coal or coke, wood and sometimes fuel oil and kerosene are combined and shown as either "other fuel" or "other.

No fuel used
Includes the three definitions below.

  • In house heating fuel data--the number of housing units that are not heated;
  • in water heating fuel data--the number of housing units without piped hot water; and
  • in cooking fuel data --the number of housing units with no cooking equipment in the unit.


Exclusive Fuel Used
Use of only one type of fuel for house heating, water heating and cooking, ascertained for occupied housing units. The types of exclusive fuel used shown separately are utility gas and electricity. The residual category "other" includes all occupied housing units where utility gas or electricity were not the fuel used exclusively for the three purposes--house heating, water heating, and cooking.

Limitations
A test survey taken before the census showed moderate to large biases in the question on fuels used. A 1970 census evaluation study found that electricity was overreported as a house heating fuel and that fuel oil and kerosene were underreported in the 1970 census.

Historical comparability
Similar data have been collected on cooking and house heating since 1940 and on water heating since 1960.

See also: Energy Costs, Monthly Residential; Heating Equipment

Full-Time/Part-Time Work
See "Hours Worked Last Week;" "Hours Worked Per Week In 1979".

Garden Apartments
See "Stories in Structure".

See "Fuel".

Government Employees
See "Class of Worker".

Grade in School
See "School Level".

Gross Rent
See "Rent, Gross".

Gross Rent as a Percentage of Income
See "Rent, Gross".

Group Quarters, Persons In
Persons in living arrangements, such as nursing homes or rooming houses, which are not households. Group quarters status was determined on a complete-count basis.

Two general categories of persons in group quarters are recognized.

Inmate of institution
A person under care or custody at the time of enumeration. Inmates are persons in such facilities as homes, schools, hospitals, or wards for the physically or mentally handicapped; persons in hospitals or wards for mental, tubercular, or chronic diseases; persons in homes for unmarried mothers; persons in nursing, convalescent, and rest homes for the aged and dependent; persons in orphanages; and persons in correctional institutions. These persons are enumerated as residents of an institution--regardless of their length of stay in the particular place and regardless of the number of people in the places. Some tabulations include data by major types of institutions (home for the aged, mental hospital, correctional institution and other institutions).

Other persons in group quarters
Persons living in group quarters who are not inmates of institutions. Rooming and boarding houses, communes, farm and nonfarm workers' dormitories, convents or monasteries, and other living quarters are classified as "other" group quarters if there are 9 or more persons unrelated to the person listed in column 1 of the census questionnaire; or if 10 or more unrelated persons share the unit. Persons residing in certain other types of living arrangements are classified as living in "other" group quarters regardless of the number or relationship of people in the unit. These include persons residing in military barracks, on ships, in college dormitories, or in sorority and fraternity houses; patients in general or maternity wards of hospitals who have no usual residence elsewhere; staff members in institutional quarters; and persons enumerated in missions, flophouses, Salvation Army shelters, railroad stations, etc.

Historical comparability
In 1970, 6 or more unrelated persons living together were classified as group quarters; for 1980 that requirement was raised to 10 or more unrelated persons.

See also: "Group Quarters Type;" "Household".

Group Quarters Type
Classification of institutions and noninstitutional quarters by the type of service provided, recorded on a sample basis for persons in group quarters. Note that statistics are provided primarily in terms of the number of persons residing in group quarters, not the number of group quarters (reported only in a subject report). See the definition for group quarters under Group Quarters, Persons In.

For those institutions which have multiple types of major service, usually general hospitals and Veterans Administration hospitals, inmates were classified by the type of care provided on their ward.

Inmate of institution
Inmate of mental hospital
Patients receiving care in mental hospitals, or psychiatric wards, or receiving mental health services in general hospitals or veteran's hospitals, or receiving care in alcoholic treatment and drug addiction centers. Basic records further discriminate among Federal, State, or local government and private mental hospitals.

Inmate of home for the aged
Persons under care in nursing, convalescent, and rest homes for the aged and dependent (including county homes, almshouses, poor farms, and fraternal or religious homes for the aged). While the great majority of these inmates are older persons, persons who are economically dependent or who require nursing care because of chronic physical conditions may be found in these homes, regardless of age. Basic records differentiate homes known to have nursing care from homes not known to have nursing care, and further classify these homes into Federal and State, county and city, private nonprofit, and private proprietary.

Inmate of correctional institution
Inmates of prisons, reformatories, local jails, and work houses. Basic records differentiate Federal, State, and local institutions. Correctional institutions are included with "Other institutions" in many tabulations.

Inmate of other institution
Inmates of hospitals or wards for tuberculosis or other chronic disease (except mental); homes, schools, hospitals, or wards for the mentally or physically handicapped, including places for the blind and deaf; orphanages and other homes for dependent and neglected children; residential treatment centers for emotionally disturbed children; training schools for juvenile delinquents; and homes for unwed mothers. Basic records classify each type separately and in many cases differentiate public from private institutions.

Other person in group quarters
In military barracks
Military personnel living in barracks or on ships. Residents of housing units on military bases are not counted here, but are included with the population in households.

In college dormitories
College students in dormitories, and sorority houses) and rooming houses exclusively for college students (provided there are 10 or more unrelated students or 9 or more unrelated to the resident who operates the place).

In rooming houses
Residents of rooming houses or other living quarters with 10 or more unrelated persons or nine or more persons not related to the person in charge, and the small number of persons temporarily residing in hotels, motels, Y's, and residential clubs who had no permanent residence elsewhere.

In other group quarters
Persons in religious group quarters (e.g., convents, monasteries, and rectories); halfway houses; communes, transient quarters, including flophouses and missions; general hospital or nurses' dormitories. Also included are crews of commercial ships, institutional staff residing in group quarters, and persons enumerated in the casual count (nonhousehold living situations such as parks, campsites, transient sites, etc.). Basic records code each type separately. Public-use microdata samples identify the eight broad categories shown above, while internal basic records show over 70 detailed types.

Historical comparability
In 1960 data on persons in military barracks were shown only for men. In 1970 and 1960 they include both men and women.

Heating Equipment
Type of heating equipment most often used, ascertained for occupied units and vacant units. Vacant units are classified by the type of heating equipment available for use by the intended occupants or that used by the previous occupants if the unit is without heating equipment. This item was asked on a sample basis.

Central heating system
Steam or hot water system
A central heating system which supplies steam or hot water to conventional radiators, baseboard radiators, heating pipes embedded in walls or ceilings, heating coils or equipment which are part of a combined heating-ventilating or heating-air conditioning system.

Central warm-air furnace
A furnace which provides warm air through ducts (passageways for air movement) leading to the various rooms. Electric heat pumps are excluded.

Electric heat pump
A combination heating-cooling system with indoor and outdoor coils, a compressor, and a refrigerant to pump hot air in during the winter and cooled air in during the summer. The heat pump may be centrally installed with ducts to the rooms, or there may be individual heat pumps in the rooms. It may also be known as a reverse cycle system.

Other built-in electric units
Electric heating units permanently installed in the floors, walls, ceiling, or baseboards which are a part of the electrical installation of the building. (Electric heating devices that are plugged into an electric socket or outlet are not built in.)

Floor, wall or pipeless furnace
Three kinds of heating methods. The question does not distinguish between them. Floor furnaces are below the floor and deliver heated air to the room immediately above or (if under a partition) to the room on each side. Wall furnaces are installed in a partition or in an outside wall and deliver heated air to the rooms on one or both sides. Pipeless furnaces are installed in basements and deliver heated air through a large register in the floor of the room or hallway immediately above.

Lacking central heating system
Room heaters with flue
Circulating heaters, convectors, radiant gas heaters, other nonportable room heaters that burn gas, oil, kerosene, or other liquid fuel, and which are connected to a flue, vent, or chimney to remove smoke and fumes.

Room heaters without flue
Any room heater (not portable) that burns gas, oil, kerosene, which is not connected to a flue, vent, or chimney.

Fireplaces, stoves, or portable room heaters
Three kinds of heating methods. The question does not distinguish between them. Fireplaces used as the principal source of heat are counted here, as are ranges and stoves, including parlor stoves, circulating heaters, cookstoves also used for heating, etc. portable room heaters can be picked up and moved around at will, either without limitation (kerosene, oil, gasoline heaters) or within the radius allowed by a flexible gas hose or an electric cord (gas, electric heaters). This classification includes all electric heaters that get current through a cord plugged into an electric wall outlet.

Units with no heating equipment. Most common in the warmest part of the country (Hawaii, Florida, etc.) and seasonal units not intended for winter occupancy.

Limitations
A test survey taken before the census showed relatively large biases for certain types of heating equipment, particularly in multi-unit structures, when compared to reinterviews. A 1970 census evaluation study found that "steam or hot water system," "central warm air furnaces," and "floor, wall, or pipeless furnace" were under reported, and that "built in electric units" and "room heaters with flue" were over-reported.

Historical comparability
Similar data have been collected since 1940. The electric heat pump category includes the central heat pumps which were part of the "central warm air furnace" category in 1970, as well as the individual room heat pumps which were included in the "built-in electric units" category in 1970. A 1970 write-in category for "other means of heating" was deleted.

See also: "Air Conditioning;" "Energy Costs, Monthly Residential;" "Fuel".

Historic Areas of Oklahoma (Excluding Urbanized Areas)
The historic areas of Oklahoma consist of the former reservations which had legally established boundaries during the period 1900-1907. These reservations were dissolved during the 2- to 3-year period preceding the statehood of Oklahoma in 1907. The former reservation boundaries are used for planning purposes by tribes and the Federal government. In the census, the entire area encompassing the former reservations was identified (except, for parts inside urbanized areas as approximated in preparation for the 1980 census). Individual former reservations were not identified separately.

The historic areas of Oklahoma (excluding urbanized areas) were assigned a unique 3-digit code by the Bureau which appears in the reservation code field. Enumeration districts (ED's), block groups (BG's), and/or portions of BG's which comprise the historic areas (excluding urbanized areas) are designated with an "A" in the ED prefix in tape files for Oklahoma.

Historical comparability
Historic areas of Oklahoma (excluding urbanized areas) were not identified in previous censuses.

Home Ownersnip
See "Tenure".

Homeowner Vacancy Rate
The number of vacant year-round units "for sale only as a percent of the total homeowner inventory, i.e., all owner-occupied units and all year-round vacant units for sale only. Vacant units that are seasonal or held off the market are excluded. This item was derived on a complete-count basis.

See also: "Vacancy Status".

Hours Worked Last Week
The number of hours actually worked at all jobs during the reference week, ascertained for all persons who reported that they worked during that week. Lunch hours, sick leave, and vacation leave are excluded, but overtime or extra hours worked in the reference week are included. Therefore, the statistics do not necessarily reflect the number of hours usually worked or the scheduled number of hours. This item was asked on a sample basis.

At work, full time
Persons who worked 35 hours or more during the reference week.

At work, part time
Persons rho worked 1 to 34 hours during the reference week. Census basic records and public-use microdata record the actual number of hours up to 99.

Limitations
The number of persons who worked only a small number of hours is probably understated since such persons sometimes consider themselves as not working. The occurrence of Passover and Good Friday in the week of April 1, 1980, should not have affected the number of reported hours worked since the reference week for most persons was the week before April 1. For those persons who completed their forms the following week, 1 or more days of the reference week may have been observed as a holiday, reducing the number of hours worked. The net effect of these holidays on hours worked statistics was probably not major nationwide, but may need to be considered in local areas where these holidays are widely observed.

Historical comparability
In 1970 and 1960, data on hours worked were recorded in intervals: 1 to 14 hours, 15 to 29, 30 to 34, 35 to 39, 40, 41 to 48, 49 to 59, and 60 or more. Data were also tabulated for l4-and 15-year-olds in selected tables.

Hours Worked Per Week In 1979
The number of hours usually worked during those weeks the person worked in 1979, generally tabulated for persons 16 years old and over who worked in 1979. If the number of hours worked per week varied considerably during 1979, an approximate average was reported. This item was asked on a sample basis.

Usually worked full time
Persons 16 years old and over who usually worked 35 or more hours per week worked in 1979.

Usually worked part time
Persons 16 years old and over who usually worked 1 to 34 hours per week worked in 1979.

Census basic records include the actual number of hours usually worked per week, up to 99. Statistics on usual hours worked in 1979, along with weeks worked in 1979, can be used to put 1979 earnings in perspective.

Limitations
Some users of microdata may attempt to calculate an average wage rate by dividing 1979 earnings by the product of weeks worked and usual hours worked per week. The usual hours worked data are probably not precise enough to yield reliable results in such a calculation.

Historical comparability
New item for 1980.

See also: "Weeks worked In 1979".

House Heating Fuel
See "Fuel".

Household
The person or persons occupying a housing unit. Counts of households, householders, and occupied-housing units are always identical in complete-count tabulations. In sample tables, the numbers may not always be the same because of differences in weighting sample data.

See also: "Household Relationship;" "Household Type;" "Housing Unit".

Household Income in 1979
Total money income received in calendar year 1979 by all household members 15 years old and over, tabulated for all households. Household income differs from family income by including income received by (a) all household members 15 years old or over, not just those related to the householder, and by (b) persons living alone and in other nonfamily households. See the definitions of Income In 1979 and Income Type for discussions of sources of income recorded, means, medians, limitations, and comparability to other data bases.

In income tables for households, the lowest income group (e.g., less than $2.500) includes households that were classified as having no 1979 income as defined in the census. Many of these were living on income "in kind," savings, or gifts; were newly created households; or were households in which the sole breadwinner had recently died or left the household. However, many of the households who reported no income probably had some money income which was not recorded in the census. Household income is recorded on public-use microdata in $10 intervals up to $75,000 or down to a net loss of 39,990 or more.

Median and mean household income figures are based on all households, unlike mean or median income figures for persons 15 years old and over, which exclude persons with no income. This item was derived on a sample basis.

Historical comparability
Household income was tabulated for the first time in the 1970 census, but its use was limited to one detailed table in PC (l)-D and the Sixth Count summary Tape. Household income is used in 1980 population reports in some places where family income was used in 1970 population reports. In 1980 as compared to 1970 housing tabulations, household income replaces "income of family or primary individual," which excluded the income of anyone unrelated to the household head. Household income is, however, derivable on public-use microdata samples from the 1960 and 1970 censuses.

See also: "Family".

Household Relationship
Relationship to the person in column 1 of the census questionnaire, ascertained from replies to a complete count question.

In household
Persons in the household include:

Householder
The person who was reported in column 1. This reference person was to be the person or one of the persons in whose name the home was owned or rented. If there was no such person, any adult household member at least 15 years old who was not a roomer, boarder, or paid employee was to be reported in column 1. In complete-count tabulations, the number of householders is the same as the number of households or occupied housing units. In sample tabulations, the numbers may not always be the same because of differences in weighting sample data.

Family householder
A householder living with one or more persons related to him or her by birth, marriage, or adoption.

Nonfamily householder
A householder living alone or only with persons not related to him or her.

Spouse
The husband or wife of the householder, living with householder. This category may include persons in common-law marriages as well as persons in formal marriages; it does not include a partner or roommate of the opposite sex. In complete-count tabulations, the number of spouses is the same as the number of married-couple families or married-couple family households. The number of spouses, however, is generally less than half of the number of married persons with spouse present" in sample tabulations, since only spouses of householders are specifically identified as "spouse." Sample tabulations of the number of married persons with spouse present include subfamilies (see definition under Family) as well as married-couple families.

A son, daughter, stepchild, or adopted child of the householder, regardless of the child's age or marital status. The category excludes sons-in-law, daughters-in-law, and foster children.

Own child
A never-married child under 18 years who is a son, daughter, stepchild, or adopted child of the householder. In certain tabulations, own children are further classified as living with two parents or with one parent only. Own children of the householder living with two parents are by definition found only in married-couple families.

Related child
An "own child" or any other family member (regardless of marital status) who is under 18 years, except the householder or spouse. Foster children are not included since they are not related to the householder.

Other relative
A household member related to the householder by birth, marriage, or adoption, but not included specifically in another relationship category. The scope of this category may differ from table to table, depending what other relationship categories are included. In detailed tabulations (STF 2 , STF 5, or PC80-l-D) the following categories may also be shown:

Parent
In complete-count tabulations, the father or mother of the householder, including a stepparent or adoptive parent. On sample basic records and microdota files, fathers- and mothers-in-law constitute a separate category coded from write-in responses under "other relative" on the questionnaire. One STF 5 and PC80-1-D tabulation includes both parents and parents-in-law in the same category.

Brother or sister
In complete-count tabulations, the brother or sister of the householder, including stepbrothers, stepsisters, and brothers and sisters by adoption. On sample basic records and microdata files, brothers- and sisters-in-law constitute a separate category coded from write-in responses. One STF 5 and PC80-1-D tabulation includes brothers- and sisters-in-law along with brothers and sisters in the same category.

Son- or daughter-in-law
Spouse of a son or daughter of the householder, coded from write-in responses.

Grandchild
Grandchild of the householder, coded from write-in responses.

The following categories are separately coded in sample basic records and public-use microdata files only: nephew/niece, grandparent, uncle/aunt, cousin, and "other."

Nonrelative
Any household member, including foster children, not related to the householder by birth, marriage, or adoption. The following categories are presented in certain more detailed tabulations.

Partner or roommate
Nonrelative who lives together and shares expenses with the householder.

Roomer or boarder
Roomer, boarder, lodger, or relative of such; or foster child or ward of the householder.

Paid employee
Nonrelative who is paid to provide household services, such as a maid, housekeeper or gardener.

Other nonrelative
Nonrelative who cannot be described by the above categories, including a person who is related to a partner or roommate or to a paid employee.

Inmate of institution and other person in group quarters
(Treated-as categories of household relationship for purposes of tabulation. For definitions, see Group Quarters, Persons In.) Persons in group quarters are excluded from counts of persons in unit.

Responses to the household relationship item were also used in defining families, and subfamilies (see Family; Family Type; Household Type). Tabulations frequently report relationship for persons in family households separately from persons in nonfamily households.

Historical comparability
The question was revised from 1970 to replace the head-of-household category with a format using a reference person, i.e., the "person in column 1." 1980 householders differ from 1970 household heads primarily where the wife in a married-couple family is listed as the "person in column 1." In 1970, the husband was automatically assumed to be the "head" of such a family. In 1980 tabulations, the substitution of one spouse for the other as the reference person may affect certain of the classifications, such as "parent" or "brother or sister," within the "other relative" grouping. The person in whose name the house or apartment is owned or rented may in a few cases differ from the person considered by other household members as the "head, but this is expected to affect the classification of relatively few households.

The 1970 questionnaire category "other relative of head" was replaced on the questionnaire by three categories, "brother/sister," "father/mother," and "other relative." Since the category "patient or inmate" is marked only by census enumerators, it was moved to the bottom of the form in a space reserved for "census use only." New nonrelative categories include "partner, roommate and "paid employee." The former question asking relationship to head of family or household was asked from 1880 to 1970.

See also: "Family;" "Family Type;" "Group Quarters, Persons In;" "Household Type".

Household Size
See "Household, Persons In;" "Persons in Unit".

Household Type
Households are classified by type according to sex of the householder and the presence of relatives based on questions asked on sex and household relationship. This item was determined on a complete-count basis.

Family household
A household including a family (See Family)

A family household may also include nonrelatives living with the family. The following subcategories are frequently provided: married-couple family; family with male householder, no wife present; and family with female householder, no husband present (see Family Type).

Nonfamily household
A household consisting of a person living alone or of a householder living with other unrelated individuals (see Unrelated Individual).

Historical comparability
In 1970, nonfamily households were termed primary individual households, a primary individual being a person living alone or the head of a household in which no relatives were present.

See also: "Family;" "Family Type;" "Unrelated Individual".

Housing Conditions, Selected
Presence of one or more of the conditions described below, determined for occupied housing units on a sample basis.

With selected conditions
With one or more of the following characteristics:

  • Lacking complete plumbing facilities for exclusive use.
  • 1.01 or more persons per room.
  • In specified renter-occupied housing units, gross rent is 30 percent or more of household income.
  • In specified owner-occupied housing units, the structure was built in 1939 or earlier and the value of the housing unit below is below a specified amount (ranging from $20,000 to $35,000) depending on metropolitan status and census geographic division.


Without selected conditions
With none of the conditions described above.

Historical comparability
Not tabulated in any previous census.

Housing Unit
A house, apartment, mobile home or trailer, group of rooms, or single room occupied as a separate living quarter or, if vacant, intended for occupancy as a separate living quarter. Separate living quarters are those in which the occupants live and eat separately from any other persons in the building and which have direct access from the outside of the building or through a common hall.

The occupants may be a single family, one person living alone, two or more families living together, or any other group of related or unrelated persons who share living arrangements (except as described in definition of Group Quarters, Persons In). For vacant units, the criteria of separateness and direct access are applied to the intended occupants whenever possible. If that information cannot be obtained, the criteria are applied to the previous occupants. Both occupied and vacant housing units are included in the housing unit inventory, except that recreational vehicles, boats, caves, tents, railroad cars, and the like are included only if they are occupied as someone's usual place of residence. Vacant mobile homes are included provided they are intended for occupancy on the site where they stand. Vacant mobile homes on dealers' sales lots, at the factory, or in storage yards are excluded from the housing inventory. Housing unit status was determined on a complete-count basis.

Historical comparability
The first Census of Housing in 1940 established the "dwelling unit" concept. Although the term became "housing unit" and the definition has been modified slightly in each succeeding census, the 1980 definition is essentially comparable to previous censuses. In 1970, the definition of a housing unit stipulated the occupants to live and eat separately and to have either direct access or complete kitchen facilities. For 1980 direct access is required; the alternative of complete kitchen facilities has been dropped. In 1970 vacant mobile homes were not counted. In 1980 vacant mobile homes are included in the housing inventory if they are intended for occupancy where they stand. Also in 1970 units with 6 or more unrelated persons living together were classified as group quarters; for 1980 that requirement was raised to 10 or more unrelated persons.

See also: "Occupancy Status;" "Tenure;" "Units At Address;" "Units In Structure;" "Year-Round Housing Units".

Income Deficit
The arithmetic difference between the total income of a family or unrelated individual and the appropriate poverty threshold, calculated for families and unrelated individuals below the poverty level. The aggregate income deficit provides an estimate of the amount of money which would be required to raise the incomes of all poor families and unrelated individuals to their respective thresholds at the poverty level. This item was derived on a sample basis.

Historical comparability
Income Deficit was first ascertained in 1970.

See also: "Income In 1979;" "Poverty Status In 1979".

Income in 1979
Total money income received in calendar year 1979, ascertained on a sample basis for all persons 15 years old and over. Total income is the sum of amounts reported separately for income from wages and salaries; nonfarm self-employment, farm self-employment; interest, dividends, and net rental; Social Security; public assistance; and all other sources.

The figures represent the amount of income received before deductions for personal income taxes, Social Security, bond purchases, union dues, medicare deductions, etc.

Receipts from the following sources were not included as income: money received from the sale of property (unless the recipient was engaged in the business of selling such property, in which case, the net proceeds would be counted as income from self-employment); the value of income "in kind" such as free living quarters or food produced and consumed in the home; withdrawal of bank deposits; money borrowed; tax refunds; exchange of money between relatives living in the same household; and gifts and lump-sum inheritances, insurance payments, and other types of lump-sum receipts. The seven specific types of income recorded are further defined under Income Type.

Income in 1979 is reported in several different combinations. Household Income in 1979 and Family Income in 1979 are defined separately in this glossary. When entitled "Income In 1979," the data refer to the money income of Persons 15 years old and over. (Where family members received income jointly, appropriate amounts were to be apportioned among specific household members.) Income in 1979 is also tabulated for "unrelated individuals 15 years old and over," i.e., persons not accounted for in family income tabulations. Where a measure of income is to be interrelated with occupation or other work force characteristics, income other than earnings is generally excluded. See Income Type -- "Earnings."

Income is tabulated in intervals, for example, less than $5.000; $5.000 to 37,499; $7,500 to $9,999 ...$35.000 to $49,999; $50,000 or more. The highest income interval to be published in reports is $50,000 or more; on summary tape files the top interval is $75,000 or more. On census basic records incomes from each source are recorded in $10 intervals up to $100,000 and in $1.000 intervals from $100,000 to $999,000. Income amounts of $l, 000,000 or more are recorded as $999,500. Net losses up to $10,000 are also recorded in ten dollar intervals. Net losses of $10,000 or more are recorded as $-9995. High incomes are grouped together on public-use microdata, with "$75.000 or more as a single category, to avoid identification of individuals.

Median income
To avoid inconsistencies in median income figures for the same population as presented in different reports, all medians for family and household income in the 1980 census are based on the same set of 17 categories available on summary tape files, regardless of the number of intervals shown in various printed tables. Thus, the median shown in a report is frequently more precise than one the user could compute from the intervals shown in the report. Pareto interpolation is used rather than linear interpolation when the width of the income interval is more than $2,500.

For families and unrelated individuals, the median income is based on the distribution of the total number of families and unrelated individuals; whereas for persons, the median income is based on the distribution of persons 15 years old and over with income.

When the median income falls in the terminal category of a distribution, the method of presentation in reports is to show the initial value of the terminal category followed by a plus sign; thus, for example, if the median income falls in the terminal category "$50,000 or more," it is shown as "$50,000 +"in reports or as "$50,001" on STF's.

Mean income
The mean income is the amount obtained by dividing the total income of a particular statistical universe (termed "aggregate income" in STF documentation) by the number of units in that universe. Thus, mean family income is obtained by dividing total family income by the total number of families. Mean income for persons is obtained by dividing the total income of persons (including patients or inmates in institutional quarters) by the number of persons with income. When the mean income for an area or population subgroup is a net loss, the dollar amount is shown preceded by a sinus sign (e.g., -$123).

Care should be exercised in using and interpreting mean income values in the statistics for small subgroups of the population. Since the mean is strongly influenced by extreme values in the distribution, it is especially susceptible to the effects of sampling variability, misreporting, and processing errors. The median is not affected by extreme values and is, therefore, a better measure than the mean when the population base is small. The mean, nevertheless, is shown for most small-area tabulations because, when weighted according to the number of cases, the means can be added to obtain summary measures for areas and groups other than those shown.

Per capita income
Per capita income is the mean income computed for every man, woman, and child in a particular group. It is derived by dividing the total income of a particular group by the total population (including patients or inmates in institutional quarters) in that group.

Limitations
Since questionnaire entries for income are frequently based on memory and not on records, many persons tend to forget minor or irregular sources of income, and, therefore, underreport their income. In addition, there are errors of reporting due to misunderstanding of the income questions. One such error is the reporting of gross instead of net dollar amounts for the two questions on net self-employment income, which results in an overstatement of these items. Such instances of overreporting would have an impact on the level of mean nonfat or farm self-employment income and mean total income.

Many reporting errors are rectified through the coding and the computer editing procedures, with the result that consistency of reported income items with work experience, occupation, and class-of-worker information is improved. For example, if a person reported that he .or she was self-employed on his or her own farm, not incorporated, but had reported wage and salary earnings only, the latter amount is shifted to net farm self-employment income. Another type of problem involves nonreporting of income. Where income information was not reported, editing and allocation procedures imputed appropriate values (either "none" or positive or negative dollar amounts) for the missing entries. These procedures will be described in more detail in appendix D, "Accuracy of the Data," to reports in the PC80-1-C and -D series.

The income data obtained in the 1980 census cover money income only. The fact that many farm families receive an important part of their income in the form of "free" goods produced and consumed on the farm rather than in money should be taken into consideration in comparing the income of farm and nonfarm residents. Nonmoney income is also received by some nonfarm residents. Such income often takes the form of business expense accounts, use of business transportation and facilities, or partial compensation by business for medical and educational expenses. Many low-income families also receive income "in kind" from public welfare programs (e.g., food stamps).

Finally, in relating income to occupation, family size, housing costs, and most other characteristics, the user must bear in mind that income figures refer to 1979 whereas other characteristics are as of the time of enumeration, generally April 1980. On the other hand, information is collected on work and unemployment in 1979, facilitating comparisons with income in 1979.

Comparability with income tax data
For several reasons, the income data from the census are not directly comparable with those which may be obtained from statistical summaries of income tax returns. Income, as defined for tax purposes, differs somewhat from the Bureau of the Census concept.

Moreover, the coverage of income tax statistics is different because of the exemptions of persons having small amounts of income and the inclusion of net capital gains in tax returns. Furthermore, members of some families file separate returns and others file joint returns; consequently, the income reporting unit is not consistently either a family or a person.

Comparability with Social Security Administration earnings record data
The earnings from the census are not directly comparable with earnings records of the Social Security Administration. The earnings data for 1979 exclude the earnings of most civilian government employees, some employees of nonprofit organizations, workers covered by the Railroad Retirement Act, and persons not covered by the program because of insufficient earnings. Furthermore, earnings received from any one employer in excess of $22,900 in 1979 are not covered by earnings records. Finally, since census data are obtained from household questionnaires, they differ from Social Security Administration earnings record data, which are based upon employers' reports and the Federal income tax returns of self-employed persons.

Comparability with Bureau of Economic Analysis income series
The Bureau of Economic Analysis (BEA) of the Department of Commerce publishes annual data on aggregate and per capita personal income received by the population for each State and selected standard metropolitan statistical areas. Aggregate income estimates based on the income statistics shown in the 1980 census would be different from (and generally less than) those shown in the BEA income series for several reasons. The Bureau of the Census data are obtained directly from households, whereas the BEA income series is estimated largely on the basis of data from administrative records of business and governmental sources. Moreover, the definitions of income are different. The BEA census income series includes some items not included in the census income data, such as income "in kind," income received by nonprofit institutions, the value of services of banks and other financial intermediaries rendered to persons without the assessment of specific charges, medicare payments, and the income of persons who died or emigrated prior to April 1, 1980. On the other hand, the census income data include contributions for support received from persons not residing in the same household and employee contributions for Social Security.

Historical comparability
Data on income last year have been collected in each census since 1940. Income questions were asked in essentially the same way in 1970 as in 1980, except that the separation of interest, dividends and net rental income from other sources is new for 1980 (possibly leading to more complete reporting of income from these sources). Another new feature was the instruction that the respondent should add up the income figures from the various sources and report total income on a separate line on the form. This feature was to help respondents avoid counting the sane income in more than one category and encourage recall of income from other sources. The 1980 census obtained income for persons 15 years old and over; the 1970 universe also included 14-year-olds.

Income intervals reported i3 1980 publications concentrate on higher dollar amounts than did their 1970 counterparts, reflecting inflation. In comparing income data for 1979 with earlier years, it should be noted that an increase or decrease in money income does not necessarily represent a comparable change in real income, unless adjustment for changes in prices is made. The ratio of the average Consumer Price Index in 1979 to the corresponding figure in 1969 is 1.98, and this is the factor used in converting 1969 median and mean income figures in current dollars to constant 1979 dollars for comparison with 1979 median and mean income figures.

See also: "Family Income In 1979;" "Household Income In 1979;" "Income Type;" "Poverty Status".

Income of Family in 1979
See "Family Income In 1979".

Income of Household in 1979
See "Household Income In 1979".

Income Type
Classification of income in 1979 by the source from which it was received, ascertained on a sample basis for all persons 15 years old and over with income. See the definition of Income In 1979 for types of receipts which are not counted as income (e.g., tax refunds).

Earnings
The sum of wage or salary income and net self-employment income from nonfarm and farm sources. Earnings are those sources of income most appropriately interrelated with labor force characteristics such as hours and weeks worked in 1979 or occupation.

Wage or salary income
Total money earnings received for work performed as an employee calendar year 1979. It includes wages, salary, pay from Armed Forces, commissions, tips, piece-rate payments, and cash bonuses earned. Sick leave pay is included. Reimbursement for business expenses and payment "in kind" (for example, food, and lodging received as payment for work performed) are excluded.

Nonfarm self-employment income
Net money income (gross receipts minus business expenses) received from an unincorporated nonfarm business, professional enterprise, or partnership in which the person was engaged on his or her own account. Gross receipts include the value of all goods sold and services rendered. Business expenses include cost of goods purchased, rent, heat, light, power, depreciation charges, wages and salaries paid, business taxes (not personal income taxes), etc. The so-called "salary" that some owners of unincorporated businesses pay themselves is included here. On the other hand, income received for working for an incorporated business, even though the person may own the business, is counted under wage or salary income.

Farm self-employment income
Net money income (gross receipts minus operating expenses) received from the operation of an unincorporated farm by a person on his own account, as an owner, renter, or sharecropper. Gross receipts include the value of all products sold, governmental subsidies, money received from the rental of farm equipment to others, and incidental receipts from the sale of wood, sand, gravel, etc. Operating expenses include the cost of fuel, fertilizer, seed, and other farming supplies, cash wages paid to farmhands, depreciation charges, cash rent, interest on farm mortgages, farm building repairs, farm taxes (not Federal, State, and local income taxes), etc. The value of fuel, food, and other farm products used for family living is not included as part of net income.

Income other than earnings
Interest, dividends, royalties, or net rental income
Money received or credited to a person's account as interest from sources such as notes, bonds, deposits in banks and savings and loan associations, credit unions, and posted savings certificates; payments made by corporations and mutual funds to stockholders (excluding profits or losses from the sale of stocks); net royalties such as income from oil, gas, and other mineral rights; from patents, copyrights on literary works, trademarks, formulas; and net rental income received from the rental of property or real estate or from roomers or boarders.

Social Security income
Cash receipts of Social Security pensions, survivors' benefits, permanent disability insurance payments, and special benefit payments made by the Social Security Administration (under the national old-age, survivors, disability, and health insurance programs) before deductions of health insurance premiums. "Medicare" reimbursements are not included nor are payments under the Supplemental Security Income program. Cash receipts of retirement, disability, and survivors' benefit payment; made by the U.S. Government under the Railroad Retirement Act are also included.

Public assistance income
Cash receipts of payments made under the following public assistance programs: aid to families with dependent children, old-age assistance, general assistance, aid to the blind, and aid to the permanently and totally disabled. These payments fire generally labeled "Supplementary Security Income" and, while usually received from the Federal government, may also be received from State or local governments. Separate payments received for hospital or other medical care are excluded from this item.

Income from all other sources
Money income received from sources such as veteran's payments; public or private pensions; periodic receipts from insurance policies or annuities; unemployment insurance benefits; workmen's compensation cash benefits; periodic payments from estates and trust funds; alimony or child support from persons who are not members of the household; receipts for foster child care; net gambling gains; nonservice scholarships and fellowships; and money received for transportation and/or subsistence by persons participating in special governmental training programs. e.g., under the Comprehensive Employment and Training Act or Work Incentive Program; and periodic contributions from persons outside the household, e.g., voluntary allotment checks sent by Armed Forces personnel to relatives not living with them.

In most reports, data on income type are limited to (1) the number of households or families with income of a specified type and (2) the mean income of the specified type for the applicable households or families (i.e., aggregate income of the specified type received by persons in households or families divided by the number of households or families with that type of income). In income type tabulations, a household or family may be counted more than once, i.e. for each type of income received, although the dollar amounts of income are counted only once. In one detailed tabulation in PC80-l-D, frequency counts are provided for income intervals as well as a mean for each type. Further, mean total income is provided in addition to mean income of specified type for households, families, and unrelated individuals with income of the specified type. The ratio of those two means will suggest the degree to which, for instance, families receiving Social Security income may also have other major sources of income.

Census basic records show income in $10 intervals for each type of income up to $100,000, except that amounts of $10,000 or more are coded as $9,995 for Social Security or public assistance income. Income amounts of $100,000 to $999,000 are recorded in $1.000 intervals. Income amounts of $l, 000,000 or more are recorded as $999,500. Net losses up to $10,000 are recorded in $10 intervals for nonfarm or farm self-employment income and interest, dividend and net rental income but are not allowed for other income types. Losses of $10,000 or more are coded as $-9995. High incomes of each type are grouped together on public-use microdata, with "$75,000 or more" as a single category, to avoid the identification of individuals.

Limitations
See the discussion under "Income In 1979."

Historical comparability
See the discussion under "Income In 1979."

Industry
The kind of business or industrial activity in which the person was employed during the reference week or, if not employed, in which the person was most recently employed since 1975. Persons working at more than one job were instructed to describe the one at which they worked the most hours during the reference week. If the employer was engaged in more than one activity, the respondent was instructed to describe only the major activity at the place or facility where the person worked. Industry is most frequently tabulated for employed persons 16 years old and over, less often for the experienced civilian labor force, which includes both employed and experienced unemployed persons 16 years old and over. Industry data were also collected but are not tabulated for persons not currently in the labor force who have worked since 1975. Industry data are collected on a sample basis.

Responses were coded to one of 231 industry categories by specially trained industry and occupation coders in census processing offices.

Most large companies were included on a Company Name List (CNL) developed from the Census Bureau economic censuses. If the company entered in question 28a was found on the CNL, the coder assigned the industry code given by the CNL. If the company could not be found on the CNL, the coder used the industry description on 28b and 28c to determine the industry code. Only the code, i.e., none of the written-in information, is retained on census basic records and public-use microdata. Census industry categories are fully defined in the Classified Index of Industries and Occupations, PHC80-R3. Persons wishing to use the census system in coding other data bases may use the Alphabetical Index of Industries and Occupations, PHC80- R4. Major industry categories and important subdivisions are as follows:

Agriculture, forestry and fisheries

Mining

Construction

Manufacturing

       Nondurable goods

       Durable goods

Transportation, communications, and other public utilities

Wholesale trade

Retail trade

Finance, insurance, and real estate

Business and repair services

Personal services

Entertainment and recreation services

Professional and related services

       Health services

       Educational services

       Other professional and related services

Public Administration

Relation to Standard Industrial Classification
The Standard Industrial Classification (SIC) system was developed under the sponsorship of the Office of Management and Budget, and subsequently under the Office of Federal Statistical Policy and Standards, and is designed for the classification of establishments by the type of industrial activity in which they are engaged. One of the major purposes of the SIC is to promote uniformity and comparability in the presentation of statistical data collected by various agencies. Accordingly, in the census of population, the industry categories are defined in these terms. However, population census data, which are collected from households, differ in nature and detail from those obtained from business establishments. Therefore, the 1980 census classification system does not reflect the full SIC detail in all categories. However, the census of population is one of the few sources of industrial data that includes all industries.

In addition to such classification differences, census data may differ from other industrial data for the following reasons: the dates to which the data refer may not be the same; workers who live in one geographic area and work in another would be reported at their place of residence by the census but at their place of work in other surveys; and dual jobholders may be counted in the reports of two establishments but counted in the census for only their major job. Many other sources for industrial data cover private employees but exclude self-employed and government workers.

Relation to certain occupation groups
Although some occupation groups are closely related to certain industries, the industry categories are broad and include occupations other than those concentrated in that industry. For example, persons employed in agriculture include truck drivers and bookkeepers in addition to farm workers; persons employed in the transportation industry include mechanics and secretaries in addition to transport operatives; and persons employed in the private household industry include occupations such as chauffeur, gardener, and secretary.

Historical comparability
There was no change in wording of the industry question from 1970. A version of this question was asked in 1820 and 1840, and consistently since 1910.

The 1970 industry categories were based on the 1967 Standard Industrial Classification (SIC) system. The 1980 classification reflects some significant changes made in the 1972 SIC manual and some minor technical adjustments made in 1977. One important change was in the census classification of public administration which was subdivided by level of government in the 1970 census, but for 1980 is classified by its primary economic activity. For example, as a result of an SIC change, the 1980 detailed tabulations include such categories as executive and legislative offices; justice, public order, and safety; and public finance, taxation and monetary policy. In 1980 most employees of governmental social service agencies are classified under social services rather than under public administration (although they are still classified as employees of a government under Class of Yorker).

More information on changes in industrial classification will be shown in later 1980 census reports. In the study of earlier data it may also be useful to refer to Technical Paper No. 26: "1970 Occupation and Industry Classification Systems in Terms of Their 1960 Occupation and Industry Elements."

More detailed changes in industrial classification are highlighted in charts in the Standard Industrial Classification Manual, 1972. Reference materials on the relationship of 1970 and 1980 industry classifications are being prepared. For more information, contact Population Division, Bureau of the Census.

See also: "Class of Worker;" "Labor Force Status;" "Occupation".

Inmate of Institution
See "Group Quarters, Persons In".

Insurance for Property, Fire, and Hazard
See "Owner Costs, Selected Monthly".

Kitchen Facilities
Presence of kitchen facilities in occupied and vacant housing units. This item was asked on a sample basis.

Complete kitchen facilities
Units with all three of the following: an installed sink with piped water, a range or cookstove (excluding portable cooking equipment), and a mechanical refrigerator (excluding ice boxes). All kitchen facilities must be located in the building or structure, but they need not all be in the same room.

No complete kitchen facilities
Units lacking one or more of the equipment items cited above, although they may have some equipment for preparing food.

Historical comparability
The 1940 and 1950 censuses asked about the Presence of a refrigerator and, in 1950, a kitchen sink, and the 1960 census added cooking facilities. The separate items were combined into one item on complete kitchen facilities in 1970, which differentiated between kitchen facilities used by this household only and those also used by another household.

Labor Force Status
Persons 16 years old and over were classified as to their status in the labor force based on replies to several questions relating to work activity and status during the reference week. These items were asked on a sample basis.

Data on labor force status refer to the calendar week prior to the date on which respondents completed their questionnaires or were interviewed by enumerators. Since the week of enumeration was not the same for all persons, the reference week for labor force data is not entirely uniform. For many persons, however, the reference week for answering the 1980 census employment questions was the last week in March, 1980.

Labor force
Members of the Armed Forces and the civilian labor force as defined below.

Armed Forces
Persons 16 years old and over on active duty in the Army, Air Force, Navy, Marine Corps and Coast Guard, (indicated in responses to the question on industry). Members of the merchant marine and civilian employees of the Department of Defense are not members of the Armed Forces. Service in a National Guard or reserve unit for short periods of active duty for training does not count as active duty in the Armed Forces.

Civilian labor force
Employed and unemployed civilians.

Employed
Civilians 16 years old and over who were either (a) "at work"--those who did any work at all as Paid employees or in their own business or profession, or on their own farm, or who worked 15 hours or more as unpaid workers on a family farm or in a family business; or (b) "with a job but not at work"-those who did not work during the reference week but had jobs or businesses from which they were temporarily absent due to illness, bad weather, industrial dispute, vacation, or other personal reasons. Excluded from the employed are persons whose only activity consisted of work around the house or volunteer work for religious, charitable, and similar organizations.

Employed persons are sometimes further classified as full time or part time based on whether they worked 35 or more hours during the reference week. (See Hours Worked Last Week.)

Unemployed
Civilians 16 years old and over who were neither "at work" nor "with a job, but not at work" and who were:

a) Looking for work during the last 4 weeks, and b) available to accept a job.

Examples of jobseeking activities are: (1) registering at a public or private employment office, (2) meeting with prospective employers, (3) checking with friends or relatives, (4) placing or answering advertisements, (5) writing letters of application, and (6) being on a union or professional register.

Also included as unemployed are persons who did not work at all during the reference week and were waiting to be called back to a job from which they had been laid off.

The concept of experienced unemployed is discussed below under Experienced Civilian Labor Force.

Not in labor force
Persons 16 years old and over who are not classified as members of the labor force. This category consists mainly of students, housewives, retired workers, seasonal workers enumerated in an "off" season who were not looking for work, inmates of institutions, disabled persons, and persons doing only incidental unpaid family work (fewer than 15 hours during the reference week). Also included are so called "discouraged workers" who do not have a job and have not been actively looking for work during the last four weeks. Inmates of institutions are occasionally presented as a subcategory within "not in labor force." Tasks performed by inmates of institutions are not considered "work" for the purposes of the census.

In addition to the above classification, the concept of Experienced Civilian Labor Force appears in certain detailed tabulations.

Experienced Civilian Labor Force
Employed persons and those unemployed persons who have worked at any time in the past, i.e., "experienced unemployed." (See Year Last Worked.) This concept serves as the universe for certain tabulations of occupation and industry where unemployed persons are to be included. (Occupation and industry data were not collected for persons who have never worked, or who have not worked since 1974.)

Comparability with data from other sources
Because employment data from the census are obtained from respondents in households, they differ from statistics based on reports from individual business establishments, farm enterprises, and certain government programs. Persons employed at more than one job are counted only once in the census and are classified according to the job at which they worked the greatest number of hours during the reference week. In statistics based on reports from business and farm establishments, persons who work for more than one establishment may be counted more than once. Moreover, other series, unlike those presented here, may exclude private household workers, unpaid family workers, and self-employed persons, but may include workers less than 16 years of age.

Historical comparability
In 1940, 1950, and 1960, labor force data were published for persons 14 years old and over. In 1970, most labor force data were for persons 16 years old and over to comply with the official Government definition of employed and unemployed instituted in 1967, although data on 14- and 15-year olds were furnished in 1970 to provide a comparability bridge with earlier censuses.

See also: "Hours Worked Last Week;" "Industry;" "Occupation;" "Labor Force Status In 1979," "Year Last Worked".

Labor Force Status in 1979
A series of items identified persons who worked in 1979 by the number of weeks worked and the number of hours usually worked per week, and persons who were unemployed in 1979 by the number of weeks unemployed. These data, collected on a sample basis, are tabulated for persons 16 years old and over regardless of current labor force status.

In labor force in 1979
Persons 16 years old and over who, at any time 1979, worked (even for a few days), were looking for work, or were on layoff from a job.

Worked in 1979
Persons who, at any time in 1973, did any work for pay or profit (including paid vacation and sick leave) or worked without pay on a family farm or in a family business, or who were on active duty in the Armed Forces.

With unemployment in 1979
Persons who looked for work or were on layoff from a job during at least one seek in 1979 in which they did not work. (Note that the question on unemployment in 1979 did not inquire whether the person was available to accept a job.)

Note that the number of persons who worked in 1979 and the number with unemployment in 1979 add to more than the number of persons in the labor force in 1979, since many of the persons with unemployment also worked at one time or another in 1979.

Historical comparability
The information on unemployment last year is new for 1980. Data on weeks of unemployment were last collected in the 1950 census.

See also: "Hours Worked Per Week In 1979;" "Weeks of Unemployment In 1979;" "Weeks Worked In 1979".

Language Spoken At Home
Persons who speak a language other than English at home were asked to report the language spoken, as well as their proficiency in English (see Language Usage and Ability to Speak English). This item was asked on a sample basis.

Respondents were instructed to report the language spoken most often, for persons speaking two or more non-English languages at home, or the first language learned, where the language spoken most often could not be determined.

The write-in entries of the language spoken were coded in census processing offices into 387 categories which arerecorded on basic records and public-use microdata files. Tables in PC30-1-C reports include the following categories:

English only, Chinese, French, German, Greek, Italian, Philippine languages, Polish, Spanish, other specified language, and unspecified language.

Data on languages spoken in the home are typically presented separately for persons 5 to 17 and 18 years old anti over. These data should not be interpreted as the number of people who are able to speak specified languages, since this question counts only persons who speak a language other than English at home.

The reported number of persons who speak a language other than English at home may be inflated slightly by a processing error. The total number of persons who speak a language other than English is inflated by approximately 0.4 percent nationwide. There is some geographic variation in the frequency of the errors, but no substantial spatial clustering has been discovered. Subsequent data products (STF 4, STF 5) will correct these errors, and thus may disagree with the estimates provided in STF 3.

Historical comparability
These data on current language are not comparable to questions asked in 1950 and 1970 on mother tongue, i.e., language other than English spoken in the person's home when he or she was a child. In 1970, Spanish mother tongue was a major determinant in the classification of "persons of Spanish heritage."

See also: "Language Usage and Ability to Speak English".

Language Usage and Ability to Speak English
Persons 5 years old and over are classified by whether they speak a language other than English at home, and, if so, by how well they speak English. Responses for persons under 5 are not tabulated. This item was asked on a sample basis.

Speak only English at home
Persons who always speak English at home. Includes persons who may speak a language other than English at school or elsewhere, but not at home, and persons whose usage of another language at home is limited to a few expressions or slang.

Speak a language other than English at home
Persons who speak a language other than English at home, even if English is spoken more frequently than the other language. They are further classified by level of English language ability:

Speak English very well
Persons who have no difficulties speaking English.

Speak English well
Persons who have only minor problems which do not seriously limit their ability to speak English.

Speak English not well
Persons who are seriously limited in their ability to speak English.

Speak English not at all
These datatypically are presented separately for persons 5 to 17 years old (school-age population) and for persons 18 years old and over, to aid the assessment of needs for bilingual education and other services.

Historical comparability
The question on current language spoken at home replaces a question asked in 1960 and 1970 on mother tongue, i.e., language other than English spoken in the person's home when he or she was a child. In 1960, mother tongue was asked only of foreign-born persons. In 1970, mother tongue was asked of all persons and vas a major determinant in the classification of "persons of Spanish heritage."

The focus on current language rather than mother tongue is a significant departure from previous censuses. The question on ability to speak English is being asked for the first time in 1980.

See also: "Language Spoken At Home".

Living Quarters
See "Group Quarters, Persons In;" "Housing Units".

See "Family Type;" "Sex".

Marital History
Persons 15 years old and over who had ever been married were asked whether they had been married more than once and, whether the first marriage ended because of the death of the person's spouse. Marital history is a construct which combines responses to these items with responses to the complete-count question on current marital status. The following items were derived on a sample basis.

Persons known to have been widowed
Widowed persons and those currently married or divorced persons married more than once whose first marriage was terminated by the death of a spouse.

Persons known to have been divorced
Divorced persons and those currently married or widowed persons married more than once whose first marriage did not end in widowhood.

Persons know to have been widowed and divorced
Widowed persons married more than once whose first marriage did not end in widowhood and divorced persons married more than once whose first marriage ended in widowhood.

Persons married only once and persons married more than once are also summarized in selected tabulations.

Historical comparability
A similar question was asked in 1970. Various questions on marital history have been asked since the 1850 census.

See also: "Age At First Marriage;" "Marital Status".

Marital Status
All persons were asked whether they were "now married," "widowed," "divorced," "separated," or "never married." Marital status data are tabulated only for persons 15 years old and older. This item was asked on a complete-count basis.

Couples who live together (unmarried persons, persons in common-law marriages, etc.) were allowed to report tile marital status they considered the most appropriate.

Single
All persons who have never been married, including persons whose only marriage was annulled.

Ever married
Persons married at the time of enumeration, including those separated, plus widowed or divorced persons.

Now married, except separated
Persons whose current marriage has ended through widowhood, divorce, or separation (regardless of previous marital history). The category may also include couples who live together or persons in common-law marriages if they consider this category the most appropriate. In certain tabulations based on sample data, currently married persons are further classified as "spouse present" or "spouse absent." See below.

Separated
Persons legally separated or otherwise absent from their spouse because of marital discord. Included are persons who have been deserted or who have parted because they no longer want to live together but who have not obtained a divorce. Separated includes persons with a limited divorce.

Widowed
Widows and widowers who have not remarried.

Divorced
Includes persons who are legally divorced and who have not remarried.

In selected sample tabulations, data for married and separated persons are reorganized and combined with information on the presence of the spouse in the same household:

Now married
All persons whose current marriage has not ended by widowhood or divorce. Includes persons categorized as separated above.

Spouse present
Married persons whose wife or husband was enumerated as a member of the same household, including those whose spouse may have been temporarily absent for such reasons as travel or hospitalization.

Spouse absent
Married persons whose wife or husband was not enumerated as a member of the same household, and all married persons living in group quarters.

Separated
Defined above.

Spouse absent, other
Married persons whose spouse was not enumerated as a member of the same household, excluding separated. Included are those whose spouse was employed and living away from home, absent in the Armed Forces, or an inmate of an institution.

Differences between the number of currently married males and the number of currently married females arise from the fact that some husbands and wives have their usual residence in different areas, and, in sample tabulations, from different weights applied to the data. Any differences between "now married, spouse present" males and females are due solely to sample weighting; by definition the numbers should be the same.

Historical comparability
The 1980 definition of "now married" is comparable to the definition of the term "married" as used in publications of data from prior censuses. For 1980, marital status is tabulated for persons 15 years old and older, a change from the period 1950-1970 when marital status was tabulated for persons 14 years old and over. A general marital status question has been asked in every census since 1880.

See also: "Marital History;" "Unmarried Couples".

Means of Transportation to Work
See "Transportation To Work;" "Means Of".

Medical Office Or Commercial Establishment
See "Owner Costs, Selected Monthly;" "Value".

Migration
See "Residence In 1975".

Minor Civil Division (MCD)
A primary political and administrative subdivision of a county. MCD's are most frequently known as townships, but in some States they include towns, magisterial districts, and similar areas. A few counties have some territory not organized into MCD's; such "unorganized territory" is treated as one or more XCD's for census purposes.

MCD's are used for census purposes in 29 States (see figure 5, column 2).In 20 of the remaining States, CCD's are used in lieu of MCDs; in Alaska, census subareas are used. In the District of Columbia, quadrants are used. In Puerto Rico, ciudades, pueblos, and barrios are used.

The Census Bureau has assigned each MCD, alphabetically sequenced within county, an incremental, unique 3-digit numeric code. In addition, MCD's in 11 States (those noted in column 4 of figure 5) have a 4-digit "MCD sequence number" which allows MCD's to be sorted into alphabetical sequence within a State.

MCD boundaries are represented on all detailed census maps. In addition, MCD outlines appear on small-scale maps published in PC80-1-A and -B and HC80-1-A reports and in conjunction with the PHC80-2 series. There are about 26,000 MCD's recognized for the 1980 census.

Statistics for all MCD's appear in STF's 1A, 2B, 3A, and 4B, and in PC80-1-A and -B and HC80-1-A reports. In 20 States (specified in column 3 of figure 5), many MCD's serve as functioning general purpose governments, and these active MCD's are included in PHC80-3 Summary Characteristics for Governmental Units and Standard Metropolitan Statistical Areas. All MCD's in block-numbered areas of these States are included in PHC80-1 Block Statistics microfiche series and STF 18. Finally, in 11 States (all 9 States in the Northeast region, plus Michigan and Wisconsin), MCD data are published in a manner parallel to that of places of the same population size in tables of PC80-1-B and -C and HC80-1-A and -B. (See figure 5, column 4.)

Historical comparability
CCD's were used in North Dakota in 1970, but for 1980 that State returned to the use of its townships. A number of MCD's in other States have changed boundaries. Changes have resulted from municipal annexations, mergers or dissolutions of MCDs, and other causes. There are seven States where MCD boundaries have changed substantially: Arkansas, Louisiana, Maryland, Mississippi, Nebraska, Virginia, and West Virginia. MCDs which have changed boundaries during 1970 to 1980 are noted in footnotes to table 4 of PC80-1-A reports for States with MCD's.

Mobile Home or Trailer
See "Units at Address;" "Units in Structure".

Mortgage Status
The existence of a mortgage, deed of trust, contract to purchase, or similar debt on the property. Land contracts, contracts for deed, and assumption agreements are included. This item was ascertained for owner-occupied one-family houses on less than 10 acres, without a commercial establishment or medical office on the property. Mobile homes or trailers and condominium units were also excluded. This item was asked on a sample basis.

Selected monthly owner costs are usually reported separately for units with a mortgage and for units not mortgaged (i.e., owned free and clear) since housing costs are quite different for the two groups.

Historical comparability
This item is new for 1980.

See also: "Owner Costs, Selected Monthly".

Municipio
See "Puerto Rico and Outlying Areas".

Nativity and Place of Birth
The population is classified into "native" and foreign born" based on the State, foreign country, Puerto Rico, or outlying area of the United States where the person's mother was living at the time the person was born (not the location of the hospital if in a different State in the United States). This item was asked on a sample basis.

Native population
Persons born in the United States, Puerto Rico, U.S. Virgin Islands, Guam, or other outlying area of the United States; or at sea or in a foreign country if they have at least one American parent (determined from the citizenship question). In certain presentations, this population is further classified as born in State of residence; born in different State (this category may be further broken down by region of birth); and born abroad, at sea, etc., of American parents.

Foreign-born population
All persons not classified as native.

Historical comparability
The format of the place-of-birth question was changed from 1970 so that the instruction to print the State where the person's mother was living at the time the person was born is highlighted so that respondents would not report the location of the hospital if in a different State from the mother's usual residence.

See also: "Country of Birth;" "State Of Birth".

Neighborhood
For purposes of the Census Bureau's Neighborhood Statistics Program, a neighborhood is a locally defined subarea of a locality. Neighborhoods must have official recognition, nonoverlapping boundaries, and a mechanism through which neighborhood residents may present their views on municipal matters.

Historical comparability
Such neighborhoods have not been recognized in past censuses.

Nonfarm, Rural
See "Farm Residence".

Nonrelative
See "Household Relationship".

Occupancy Status
The classification of all housing units as either occupied or vacant. This item was determined on a complete-count basis.

Occupied
A housing unit occupied as the usual place of residence of a person or group of Persons living in it at the time of enumeration, or by occupants only temporarily absent such as on vacation. A household consists of all the persons who occupy a housing unit as their usual place of residence. If all the persons staying in the unit at the time of enumeration have their usual place of residence elsewhere, the unit is classified as vacant. Complete count figures on households and occupied housing units should match--although sample estimates of households and occupied housing units may differ because of weighting.

Vacant
A housing unit with no one living in it at the time of enumeration, unless its occupants are only temporarily absent. If, at the time of enumeration, the unit is temporarily occupied solely by persons who have a usual residence elsewhere, it is also classified as vacant.

New units not yet occupied are classified as vacant housing units if construction has reached a point where all exterior windows and doors are installed and final usable floors are in place.

Vacant units are excluded if open to the elements; that is, if the roof, walls, windows, or doors no longer protect the interior from the elements, or if there is positive evidence (such as a sign on the house or in the block) that the unit is to be demolished or is condemned. Also excluded are quarters being used entirely for nonresidential purposes, such as a store or an office, or quarters used for the storage of business supplies or inventory, machinery, or agricultural products.

Historical comparability
Similar data have been collected since 1940.

See also: "Vacancy Status".

Occupation
The kind of work the person was doing at a job or business during the reference week or, if not at work, at the most recent job or business if employed since 1975. Persons working at more than one job were instructed to describe the one at which the person worked the most hours during the reference week. Occupation is most frequently tabulated for employed persons 16 years old and over, and less often for the experienced civilian labor force, which includes both employed and experienced unemployed 16 years old and over. Occupation data were also collected but are not tabulated for persons not currently in the labor force who have worked since 1975. Occupation is not determined for persons in the Armed Forces. These data were collected on a sample basis.

The write-in responses to questions 29a and 29b were taken together to assign the respondent to one of 503 occupation categories, coded by specially trained industry and occupation coders in census processing offices. Only the code, i.e., none of the written-in information, is retained on census basic records and public-use microdata. Census occupation categories are fully defined in the Classified Index of Industries and Occupations, PHC80-R3. (Persons wishing to use the census system in coding other data bases may use the Alphabetical Index of Industries and Occupations, PHC80-R4.)

Relation to Standard Occupational Classification
The 503 occupation categories generally are based on the Standard Occupational Classification (SOC) system, originally issued in 1977 by the Office of Federal Statistical Policy and Standards and revised in 1980. One of the major purposes Of the sot is to promote uniformity and comparability in the presentation of occupational data collected by various agencies. Public use microdata documentation and other references will define the relationship between the 3-digit census codes and the revised 4-digit SOC codes.

Summary and major occupation categories are as follows:

Managerial and professional specialty occupations:
  • Executive, administrative, and managerial occupations
  • Professional specialty occupations

Technical, sales, and administrative support occupations:
  • Technicians and related support occupations
  • Sales occupations
  • Administrative support occupations, including clerical

Service occupations:
  • Private household occupations
  • Protective service occupations
  • Service occupations, except protective and household

Farming, forestry, and fishing occupations

Precision production, craft, and repair occupations

Operators, fabricators, and laborers:
  • Machine operators, assemblers, and inspectors
  • Transportation and material moving occupations
  • Handlers, equipment cleaners, helpers, and laborers

These are the categories included in STF 3 and Census Tracts reports. More detailed tabulations present subcategories within these basic groups. In the most detailed tabulations, some categories represent subdivisions of an occupation on the basis of industry or class of worker.

Historical comparability
Occupation has been asked in each census since l850. The 1980 occupation question differs from its 1970 counterpart primarily by omitting a request for the respondent's job title. Because this information sometimes proved misleading, it was dropped for 1980.

The major difference in occupation data for 1970 and 1980 stems from the adaptation of census occupation coding to the new Standard Occupational Classification system, first issued in 1977. While many of the broad categories observed in the, 1980 scheme have been designed to offer a general measure of compatibility with many 1970 categories, the principles governing the classification and many of the detailed categories have been altered substantially. Reference materials on the relationships of 1970 and 1980 occupation classifications are being prepared. For more information, contact Population Division, Bureau of the Census.

See also: "Class of Worker;" "Industry;" "Labor Force Status".

One-Family Homes
See "Units in Structure".

One-Person Households
See "Household, Persons In".

One-Unit Structures
See "Units in Structure".

Other Races
See "Race".

Outlying Areas
See "Puerto Rico and Outlying Areas".

Overcrowding
See "Persons per Room".

Owner Costs, Selected Monthly
The sum of payments for real estate taxes, fire and hazard insurance, utilities, fuels, and mortgage. These data are tabulated for "specified owner-occupied" units, i.e., one-family houses on less than 10 acres without a commercial establishment or medical office on the property. The data exclude owner-occupied condominiums, mobile homes, and trailers.

Only selected monthly owner costs are included, since payments for maintenance and repair are excluded. Selected monthly owner costs are presented in tabulations comparable to those for gross rent since they are both measures of shelter costs) albeit for different universes.

The components of selected monthly owner costs are payments for the following items, all asked on a sample basis:

Real estate taxes
The total amount of all real estate taxes payable on the entire property (land and buildings) last year. It includes State, local, and all other real estate taxes even if delinquent, unpaid, or paid by someone outside the household. Taxes are reported even if included in the mortgage payment. Not covered are payments on delinquent taxes due from earlier years.

Fire and hazard insurance
The annual premium for fire and hazard insurance on the property; that is, policies which protect the property and its contents against loss due to damage by fire, lightning, winds, hail, explosion, etc. Liability policies are included only if they are paid with fire and hazard premiums and the amounts for fire and hazard cannot be separated. Premiums are included even if paid by someone outside the household or remain unpaid.

Mortgages
The regular monthly amount (both principal and interest) required by the lender on mortgages (including second or junior mortgages), deed of trust, or similar debt on the property; or payments on a contract to purchase the property. Amounts are included even if the payments are delinquent, or paid by someone else. The amount includes everything paid to the lender or lenders, regardless of what is included. Separate parts of the question determine whether taxes and insurance are included in the payment to the lender so that it is possible to avoid counting these components twice in the computation of monthly owner costs.

Utilities and fuel
See the discussion under Energy Costs, Monthly Residential.

In the computation of selected monthly owner costs, annual figures for taxes, insurance, water and fuels (items where annual figures are usually more readily available than monthly figures) are divided by 12 to yield monthly figures.

Selected monthly owner costs are tabulated in a varying number of categories. Data are generally presented separately for units with a mortgage and units not mortgaged (i.e., owned free and clear) since the distribution of housing costs is quite different for the two groups. Basic record tapes preserve the dollar amounts for each of the component figures collected (e.g., mortgage payments, water payments). Public-use microdata samples also show dollar amounts, for components as well as tot31 selected monthly owner costs, although the amounts for real estate taxes and insurance premiums are combined into a single figure.

Selected Monthly Owner Costs As Percentage of Income

The ratio of selected monthly owner costs to household income in 1979) converted to percentage form. The data are tabulated for "specified owner occupied" units, i.e., one-family houses on less than 10 3cres without a commercial establishment or medical office on the property. The data exclude owner-occupied condominiums, mobile homes, and trailers.

Data are shown in terms of the number of housing units in categories such as "less than 20 percent," "20 to 24 percent," "25 to 34 percent," and "35 percent or more;" the data are generally cross classified by household income. Units occupied by households reporting no income or a net loss are included in the "not computed" category. This item was computed on a sample basis.
Limitations: Utility and fuel costs are frequently overestimated by respondents.

Historical comparability
None of the components of selected monthly owner costs have been collected in previous censuses. (Utility and fuel costs were collected in 1970, but only for renters.)

Owner-Occupied Housing Units
See "Tenure".

Owner/Renter Status
See "Tenure".

Pacific Islander Population
See "Race".

Parish (In Louisiana)
See "County".

Passenger Elevator
See "Elevator in Structure".

Person in Column 1
See "Household Relationship".

Persons in Household
The number of persons living in the housing unit. All occupants are counted--not just those related to the householder, but also any lodgers, roomers, hoarders, partners, wards, foster children, and resident employees who share the living quarters.

Figures for "persons in household" match those for "persons in unit" in tabulations based on complete-count data. In sample tabulations, they may differ because of the weighting process. The phrase "persons in household" is used for population tabulations, "persons in unit" for housing items. "One-person households" and "persons living alone" are synonymous.

Persons in Unit
See "Persons in Household".

Persons per Room
A derived measure obtained by dividing the number of persons in each occupied housing unit by the number of rooms in the unit. The figures shown refer, therefore, to the number of housing units having the specified ratio of persons per room. For example, the number of units with 1.01 or more persons per room is the number of units occupied by more persons than there are separate rooms. This item was derived on a complete-count basis.

See also: "Rooms".

A concentration of population which may or may not have legally prescribed limits, powers, or functions. Most of the places identified in the 1980 census are incorporated as cities, towns, villages, or boroughs. In addition, census designated places (called "unincorporated places" in earlier censuses) are delineated for 1980 census tabulations. There are about 23,000 places recorded in the 1980 census. Places do not cross State boundaries.

Incorporated place
A political unit incorporated as a city, borough (excluding Alaska and New York), village, or town (excluding the New England States, New York, and Wisconsin). In most States, incorporated places are subdivisions of the MCD or CCD in which they are located; for example, a village located within and legally part of a township. In some States, incorporated places are independent of surrounding township or towns and therefore are also treated as MCD's. In a few states, the pattern is mixed. Almost 4,000 incorporated places cross MCD/CCD and/or county boundaries.

There are about 20,000 incorporated places recognized in the 1980 census.

Census designated place (CDP)
A densely settled population center without legally corporate limits or corporate limits or corporate powers or functions. Each CDP has a definite residential nucleus with a dense, city-type street pattern, and ideally should have an overall population density of at least 1,000 persons per square mile. In addition, a CDP is a community that can be identified locally by place name. Boundaries of CDP's are drawn by the Census Bureau, in cooperation with State and local agencies, to include, insofar .3S possible, all the closely settled area. In the 1980 census, statistics are tabulated for each CDP with 5,000 inhabitants or more if located in an urbanized area (UA) with a central city of 50,000 or more and for each CDP of 1,000 inhabitants or more if in a UA with no central city of 50,000 or more. Some CDP's--notably in the Northeast-- coincide with MCD's. In STF's, these are treated as both places and MCD's, but in printed reports they are show only in MCD tables to avoid duplication. Outside of UA's, statistics are tabulated in 48 States and Puerto Rico for CDP's of 1,000 or more, in Hawaii for CDP's of 300 or more, and in Alaska for CDP's of 25 or more.

There are approximately 3,400 CDP's recognized in the 1980 census.

Incorporated place and CDP boundaries are shown on all detailed census maps. For tracted areas, boundaries of all places are shown on census tract outline maps. County subdivision maps, at a still smaller scale, also show boundaries for places.

A 4-digit numeric code is assigned by the Census Bureau to each place in alphabetic sequence within State. "Place description" codes will also generally accompany place records. These codes indicate whether a place is incorporated, as well as represent certain other information about the place.

Data are summarized for all places in STF's 1A and 3A, and PC80-l-A reports. For places with 1,000 or more inhabitants, data are summarized in STF 2B, and PCBO-1-B and HC80-1-A reports. For places with 2,500 or more, data are summarized in STF 4B, PC80-1-C, and HC80-1-B reports. In PHC80-3 reports, data are given for all incorporated places. In PHC80-2 Census Tracts reports and STF's 2A and 4A, summaries are presented only for places with 10,000 or more inhabitants located in tracted areas. Very detailed data are presented for all places which are central cities of SMSA's in PC80-1-D reports, and places with 50,000 or more inhabitants in HC80-2 reports. STF 5 also provides detailed data for places of 50,000 or more.

The files and reports which sequence geographic units in hierarchical fashion must account for the fact that places nay cross the boundaries of counties, MCD's, and CCD's. Such reports and tapes, therefore, provide summaries for the various parts of places created when places are split by the boundaries of higher level areas recognized in the hierarchy. Specifically, place parts within county and MCD or CCD are presented in STF 1A and 3A, and PC80-1-A reports. Place parts within county and MCD are presented for 20 specified States and Puerto Rico in STF 1B and PHC80-1 Block Statistics microfiche reports, but the PHC80-1 reports include only places which have data collected for blocks. In the remaining 30 States, STF 1B and PHC80-1 reports subdivide places when split by county boundaries, but do not observe MCD or CCD boundaries.

Historical comparability
Sixty-eight percent of all incorporated places of 2,500 or more made changes in their boundaries between 1970 and January 1, 1980, which is the reference date for boundaries in the 1980 census. In the 1970 census, ED boundaries were draw so as to allow a user to aggregate 1970 data for each city of 2,000 or more inhabitants according to 1960 boundaries. There will not be a corresponding capability in the 1980 census.

In the 1970 and earlier censuses, CDP's were referred to as "unincorporated places." The name was changed to make it more explicit that such places are defined for census purposes, and to avoid confusion in States where many "unincorporated places" are parts of incorporsted towns or townships. Many CDP's have been redefined since 1970. Incorporated places which were newly incorporated or which changed boundaries between 1970 and 1980 are listed in footnotes to table 4 of PC80-1-A reports.

Place of Work
The geographic location of the plant, office, store, or other establishment where the person worked most last week (see the discussion of reference week under Labor Force Status), ascertained for persons at work last week, including both civilian employed and Armed Forces at work, and tabulated for persons 16 years old and over. These data were obtained on a sample basis.

If the person worked at more than one location for the same employer (such as a grocery store chain or public school system), the exact address of the location or branch where the respondent worked most last week was requested. Persons working at more than one job were asked to report the location of the job at which they worked the greatest number of hours during the census week. Salespersons, delivery persons, and others who worked in several places each week were requested to give the address at which they began work each day, if they reported to a central headquarters. For cases in which daily work was not begun at a central place each day, the person was asked to report the exact address of the place where he or she worked the most hours last week.

Responses were coded in census processing offices but only for a sample of approximately one-half of the long-form questionnaires (a cost-saving measure). All entries were assigned codes which define the work location in terms of State, county, place of 2,500 or more (1,000 or more in Alaska and Hawaii) as estimated prior to the census, or in the Northeast region, minor civil division. For residents of SMSAs, place of work was coded further to tract and block (if in a blocked area) if the place was within the same SMSA or multi-SMSA commutershed.

Place-of-work tabulations vary considerably from one publication series to another. PC80-1-C reports furnish data for each of the following categories:

All workers

Place of work reported

Worked in area of residence

Worked outside area of residence

Percent of those reporting place of work

Place of work not reported

In these tabulations, the place of work is shown in terms of whether or not it is within the "area of residence," the definition of which varies with the geographic summary level. For instance, if a given column in a table presents data for a county, the place of work lines indicate the number of county residents who work inside and outside that county.

Census Tracts (PHC80-2) reports present up to 20 place-of-work categories for SMSA's, SMSA counties, places of 10,000 or more in SMSA'S, and census tracts as illustrated in the following list:

Inside SMSA

       Omaha, Nebr. central business district

       Remainder of Omaha city, Nebr.

       Remainder of Douglas County, Nebr.

       Bellevue city, Nebr.

       Remainder of Sarpy County, Nebr.

       Council Bluffs city, Iowa

       Carter Lake city, Iowa

       Remainder of Pottawattamie County, Iowa

Outside SMSA

       Lincoln city, Nebr.

       Remainder of Lancaster County, Nebr.

       Cass County, Nebr.

       Fremont city, Nebr.

       Remainder of Dodge County, Nebr.

       Washington County, Nebr.

       Mills County, Iowa

       Elsewhere

Place of work not reported

Up to 20 separate work locations are recognized in these PHC80-2 tabulations and on STF 4. The same 20 locations are used throughout each SMSA, but they vary from SXSA to SMSA and from county to county in nonmetropolitan areas.

Special tabulations can be prepared at user expense which make use of the additional detail available on census basic records. For instance, tabulations can be generated which show commuter flows by origin and destination in terms of census tracts within a given SMSA or multi-SMSA commutershed. Characteristics of workers by place of work can also be tabulated.

Public-use microdata "A" and "B" samples report place of work in the same terms as place of residence, i.e., States and "county groups" with 100,000 or more inhabitants. Within large SMSA's, individual counties and places over 100,000 are frequently identified as county groups making possible some analysis of commuting patterns by commuter characteristics. The "C" sample identifies place of work in central cities and in places in four size categories.

Limitations
It should be noted that place-of-work tabulations do not necessarily give the total number of persons who work in the specified area, only those who also reside within the area summarized. In the above example, the number reported as working in the central business district would not include workers who commute from outside the SMSA being summarized.

Since Place of Work was coded only for a sample of one-half of all long-form questionnaires, along with Residence in 1975 and Travel Time to Work, it required an estimation scheme which differed from that used for full-sample items. As a consequence, the estimated number of workers 16 and over 35 derived from place-of-work tabulations will differ somewhat from the corresponding figure derived from tabulations of Means of Transportation to Work, a full sample item. Further, any cross-tabulation of place of work by other items is necessarily based only on the half-sample.

Historical comparability
Place of work was asked first in 1960, when the inquiry was limited to the State, county, and city of work. In 1970, the question took on its current form, requesting the specific street address and ZIP code. A higher percentage of cases was successfully coded to tract and block of work in 1980 than in 1970, due to improvements in coding materials.

Data on place of work tabulated for inside and outside the area of residence, as discussed above, are new for 1980.

See also: "Transportation to Work, Means Of;" "Travel Time to Work".

Plumbing Facilities
Presence of toilet facilities, bathing facilities, and piped water, ascertained for occupied and vacant housing units. This item was asked on a complete-count basis.

Complete plumbing for exclusive use
Piped hot and cold water, a flush toilet, and a bathtub or shower for exclusive use by household members. All facilities must be in the living quarters, but need not be in the same room. Hot water need not be available continuously. A privy or chemical toilet is not counted as a flush toilet. A bathtub or shower is counted only if it is connected to piped running water.

Lacking complete plumbing for exclusive use:

Complete plumbing facilities, but also used by another household
All facilities preset, but with some or all of the plumbing facilities also regularly used by someone who is not a member of the household. This category also applies if the future occupants of living quarters now vacant would be expected to share the facilities.

Some but not all plumbing facilities
Units with one or two but not all three of these: hot and cold piped water, flush toilet, and bathtub or shower.

No plumbing facilities
Historical comparability
Data on plumbing facilities have been collected since 1940. In 1970, there were separate questions on presence of hot and cold running water, a flush toilet, and a bathtub or shower. The questions were combined in 1980. In 1980 complete facilities must not only be in the building, as in 1970, but also inside the housing unit.

See also: "Bathrooms;" "Water, Source Of".

Poverty Status In 1979
Families and unrelated individuals are classified as above or below the poverty level by comparing their total 1979 income to an income cutoff or "poverty threshold." The income cutoffs vary by family size, number of children, and age of the family householder or unrelated individual. Poverty status is determined for all families (and, by implication, all family members). Poverty status is also determined for persons not in families, except for inmates of institutions, members of the Armed Forces living in barracks, college students living in dormitories, and unrelated individuals under 15 years old. Poverty status is derived on a sample basis.

The 1980 census definition of poverty reflects revisions recommended by a Federal interagency committee in 1979 to a definition adopted in 1969. The index is based on the Department of Agriculture's 1961 Economy Food Plan and reflects the different consumption requirements of families based on their size and composition. It was determined from the Department of Agriculture's 1955 survey of food consumption that families .of three or more persons spend approximately one-third of their income on food; the poverty level for these families was, therefore, set at three times the cost of the economy food plan. For smaller families and persons living alone, the cost of the economy food plan was multiplied by factors that were slightly higher in order to compensate for the relatively larger fixed expenses of these smaller households. The poverty thresholds are updated every year to reflect changes in the Consumer Price Index (CPI). Cutoffs for 1979 income used in poverty statistics in the 1980 census are presented below. As an example, the poverty threshold for a family of four with two related children under 18 can be found in the chart below to be $7,356 in 1979.



Poverty thresholds are computed on a national basis only. No attempt has been made to adjust these thresholds for regional, State, or other local variations in the cost of living.

The poverty status of a person who is a family member is determined by the family income and its relationship to the appropriate poverty threshold for that family. The poverty status of an unrelated individual is determined by his or her own income in relation to the appropriate poverty threshold. Thus, two unrelated individuals living together may not have the same poverty status.

Households below the poverty level are defined as households in which the total income of the family or the householder of a nonfamily household is below the poverty level. The incomes of persons in the household other than members of the family or other than the householder in a nonfamily household are not taken into account when determining poverty status of a household.

Because the poverty levels currently in use by the Federal Government do not meet all the needs of the analysts of the data, variations of the poverty definition are available in terms of various multiples of the official poverty levels. The one most frequently tabulated is 125 percent of the poverty level, where a family or person may have up to 25 percent more income than normally allowed under the poverty threshold appropriate for the family size, etc.

Below poverty level ("poor")
Families or persons whose total family income or unrelated individual income in 1979 was less than the poverty threshold specified for the applicable family size, age of householder, and number of related children under 13 present. In certain tabulations, this group is further subdivided into those with income "below 75 percent of poverty level" and "between 75 and 99 percent of poverty level."

Above poverty level ("nonpoor")
Families or persons whose total family income or unrelated individual income in 1979'was equal to or greater than the poverty threshold specified for the applicable family size, etc. In certain tabulations, this group is further subdivided into those with income "between 100 and 124 percent of poverty level," "between 125 and 149 percent of poverty level," "between 150 and 174 percent of poverty level, "between 175 and 199 percent of poverty level," and "200 percent of poverty level and above."

Limitations
The team "poverty" connotes a complex set of economic, social, and psychological conditions. The standard statistical definition provides only estimates of economic poverty based on the receipt of money income before taxes. Excluded from the income concept is a measure of the benefits derived from the receipt of in-kind government transfers, such as food stamps, medicaid, and public housing; private transfers such as health insurance premiums paid by employers; the value of the services obtained from the ownership of assets, such as owner-occupied housing units; and the receipt of money from the sale of property, withdrawal of bank deposits, gifts and money borrowed. A comprehensive review of the current poverty definition and its limitations can be found in The Mea sure of Poverty, U.S. Department of Health, Education, and Welfare, April 1976. See also the discussion of limitations under Income In 1979.

Historical comparability
Poverty statistics were first included in a decennial census in 1970. Prior to 1980 the poverty thresholds did not distinguish among families with 7, 8, and 9 or more persons; on the other hand, the cutoffs were further differentiated by the sex of the family head or unrelated individual and by farm/nonfarm residence. In the 1970 census, the thresholds for farm residents were set at 85 percent of the thresholds for nonfarm residents. 1979 income thresholds used in the 1980 census represent a weighted average of the nonfarm thresholds used in the past male headed and female headed families. The elimination of the 85-percent threshold for farm families increased the farm population classified as poor by about 174,000 persons or about one-fifth nationwide. The net effect of all three changes on the total number of poor persons is to increase it approximately 380,000 or 1.5 percent.

Since the poverty income cutoffs have been adjusted each year for changes in the CPI, and since the overall impact of the definitional changes is minimal, 1980 census poverty figures for the total and nonfarm population should be reasonably comparable to the 1970 poverty figures. However, because of the definitional changes cited, comparisons involving the farm population should be made with caution.

See also: "Income Deficit".

Precinct
See "Election Precinct".

Price Asked
See "Value".

Private Vehicle Occupancy
See "Vehicle Occupancy".

Property Insurance
See "Owner Costs, Selected Monthly".

Public Sewer Facilities
See "Sewage Disposal".

Public Transportation Disability
See "Disability".

Public Water Supply
See "Water, Source Of".

Puerto Rico and Outlying Areas
In addition to the United States, the decennial census covers the Commonwealth of Puerto Rico and the outlying areas, including American Samoa, Guam, the Trust Territory of the Pacific Islands (including the Northern Mariana Islands which were legally part of the Trust Territory in 1980), the U.S. Virgin Islands, and certain other small islands over which the United States exercises sovereignty or jurisdiction. Questionnaire design and the questions asked were developed for Puerto Rico and each outlying area to accommodate local conditions. In the case of some small or military-occupied islands, enumerations were not conducted; only population counts obtained from U.S. Government records are published.

The geographic subareas for which statistics are reported vary. Some of those noted below are defined in this glossary; others will be defined in 1980 census reports for the areas.

  • American Samoa: villages, district subdivisions, districts, and islands.
  • Guam: census designated places and election districts.
  • Northern Mariana Islands and the remainder of the Trust Territory of the Pacific Islands: census designated places, municipal districts, municipalities and islands, and administrative districts.
  • Puerto Rico: blocks; ED's and BG's; census tracts and block numbering areas; zonas urbanas and aldeas; subbarrios; barrios, ciudades, and pueblos; municipios; and SMSA's and SCSA's.
  • Virgin Islands: places, census subdistricts, and islands.
  • Other islands: no subdivisions.

Data for Puerto Rico and its subdivisions will appear in reports and tapes in generally the same pattern as for States and their subdivisions. Data for outlying areas will appear in 1980 Census of Population, Volume 1, and 1980 Census of Housing, Volume 1, reports, and on STF's 1 and 3.

Historical comparability
The Canal Zone was not included in the 1980 census because it was no longer under U.S. jurisdiction.

All persons wore asked to identify themselves according to the following race categories on the 1980 questionnaire: White, Black or Negro, American Indian, Eskimo, Aleut, Japanese, Chinese, Filipino, Korean, Asian Indian, Vietnamese, Hawaiian, Guamanian, Samoan, and Other. The "Other" category includes Malayan, Polynesian, Thai, and other groups not included in the specific categories listed on the questionnaire. This item was asked on a complete-count basis.

The concept of race as used by the Census bureau reflects self-identification by respondents; it does not denote any clear-cut scientific definition of biological stock. Since the 1980 census obtained information on race through self-identification, the data represent self-classification by people according to the race with which they identify themselves. For persons with parents of different races who could not provide a single response to the race question, the race of the person's mother was used; however, if a single response could not be provided for the person's mother, the first race reported by the person was used.

Counts of the population by race in complete-count tabulations are provisional. Final counts for race will be determined after the sample data have been processed. The sample counts will first appear on tape on STF 3 and in print in Characteristics of the Population, General Social and Economic Characteristics (PC80-1-C) reports.

Limited edit and review operations were performed during the complete-count operations; write-in responses were reviewed in an attempt to classify entries to specific categories, where appropriate. For instance, if the "Other" circle was marked with a write-in entry "Caucasian," then the response was recoded as White. (Additional examples are noted below.) However, all such cases were not identified in the complete-count processing. During the processing of sample questionnaires, a more thorough review and additional editing was done to resolve inconsistent or incomplete responses. Also, during the processing of sample questionnaires, write-in entries for the "Other" category were assigned specific codes, which is included on the person's basic record in the census sample detailed tape files.

Asian and Pacific Islander write-in entries, such as Indo-Chinese, Cambodian, or Polynesian, included in the "Other" category during 100-percent processing, are collectively tabulated and shown as "Other Asian and Pacific Islander" in the census sample tabulations; this group, "Other Asian and Pacific Islanders," will be included in the broader Asian and Pacific Islander category in all sample tabulations by race. This shift of "Other Asian and Pacific Islander" entries out of the "Other races" category in sample tabulations and the recoding of write-in entries in the "Other" category to specific categories where appropriate Will affect the comparability between complete-count and sample data for some groups.

Persons who indicated their race as White, as well as persons who did not classify themselves in one of the specific race categories listed on the questionnaire but entered a response such as Canadian, German, Italian, Lebanese, or Polish. (Persons who did not classify themselves in one of the specified race categories but wrote in entries such as Cuban, Puerto Rican, Mexican, or Dominican were included in the "Other races" category; in the 1970 census most of these persons were included in the "White" category.)

Persons who indicated their race as Black or Negro, as well as persons who did not classify themselves in one of the specific race categories, but reported entries such as Black Puerto Rican, Haitian, Jamaican, Nigerian, or West Indian.

American Indian, Eskimo, and Aleut
American Indian
Persons who indicated their race as "Indian (American)" or who did not indicate a specific race category but reported the name of an Indian tribe.

Eskimo
Persons who indicated their race as "Eskimo."

Persons who indicated their race as "Aleut."

Asian and Pacific Islander
In complete-count tabulations, includes all of the groups listed below except "Other Asian and Pacific Islander." In sample tabulations, it includes all of the groups listed below.

Japanese
Persons who indicated their race as Japanese, as well as persons who did not classify themselves in one of the specific race categories, but entered a response such as Nipponese or Japanese American.

Chinese
Persons who indicated their race as Chinese, as well as persons who did not classify themselves in one of the specific race categories, but reported entries such as Cantonese, Formosan, Taiwanese, or Tibetan.

Filipino
Persons who indicated their race as Filipino, as well as persons who did not classify themselves in one of the specific race categories, but entered a response such as Filipino American or Philippine.

Korean
Persons who indicated their race as Korean, as well as persons who did not classify themselves in one of the specific race categories, but reported a response such as Korean American.

Asian Indian
Persons who indicated their race as Asian Indian, as well as persons who did not classify themselves in one of the specific race categories, but reported entries such as Bengali, Bharati, Dravidian, East Indian, Goanese, Hindu Indic, Kashmiri, or South Asian.

Vietnamese
Persons who indicated their race as Vietnamese, as well as persons who did not classify themselves in one of the specific race categories, but reported a response such as Vietnam.

Hawaiian
Persons who indicated their race as Hawaiian. In the State of Hawaii, al1 persons who reported "Part-Hawaiian" were included in this category. Guamanian. Persons who indicated their race as Guamanian, as well as persons who did not classify themselves in one of the race categories, but reported an entry such as Chamorro or Guam.

Samoan
Persons who indicated their race as Samoan, as well as persons who did not classify themselves in one of the specific race categories, but entered a response such as American Samoan or Western Samoan.

Other Asian and Pacific Islander
In sample tabulations only, persons who reported Cambodian, Hmong, Indo-Chinese, Laotian, Pakistani, Polynesian, Fiji Islander, Tahitian, Thai, or similar responses. Census basic records include codes for over 50 separate race group s within this category. In complete-count tabulations, this group is part of the "Other races" category below.

Other (Race n.e.c. "not elsewhere classified")
Includes all other races (except "Other Asian and Pacific Islander" groups) which were not included in the specific categories listed on the questionnaire. For example, persons reporting in the "Other" race category and providing write-in entries such as Eurasian, Cosmopolitan, Inter-racial, or a Spanish origin group (e.g., Mexican, Cuban, or Puerto Rican) were included in Race, n.e.c. Other Asian and Pacific Islanders are included in the "Other" category in 100-percent tabulations. Persons who did not report a specific race but wrote in entries such as "Mexican," "Cuban," "South American, "Chicano," or "La Raza" remained in the "Other races" category for complete-count tabulations, and in the "Race, n.e.c." category for sample tabulations. (STF 3, STF 4, and public-use microdata samples separately identify, as a subcategory within "Race. n.e.c.," persons who wrote in an entry implying Spanish origin. Such entries are not necessarily consistent with responses in the Spanish origin question.)

In a few tables in which data for American Indian, Eskimo, Aleut, and Asian and Pacific Islander are not presented separately, the "Other" category encompasses all race categories not shown separately.

In some tabulations, the "Other" or "Race, n.e.c." category is omitted to save space; data for this category are derivable by subtracting the sum of the specified race categories from the total.

In certain printed tables, where space is limited, data for persons of Spanish origin are presented alongside data for up to four major race groups. In such situations, users should not be misled by the proximity of these two types of data. Spanish origin is not a race category, and persons of Spanish origin may be of any race. Tabulations in a number of sources present data separately for race categories (e.g., White, Black, and "Other") for persons not of Spanish origin. In addition, the number of Spanish-origin persons is given by race.

Limitations
In previous censuses, undercoverage of the population has been associated with race. The 1970 census missed Blacks at a much higher rate than Whites. The Bureau has not prepared undercoverage rates for races other than White or Black, because vital records and other sources of relevant statistics do not consistently distinguish among other races.

Historical comparability
Questions on "race" or "color" have been asked in each census since 1790. In 1970, when persons with parents of different races were in doubt 8s to their classification, the race of the father was used. In 1980, the race of the mother was used for persons who could not provide a single response. The 1970 category "Negro or Black" has been retitled "Black or Negro. Individual categories for Vietnamese, Asian Indian, Guamanian, and Samoan have been added. In 1970, the categories Eskimo and Aleut appeared only on questionnaires used in Alaska; they were replaced by Hawaiian and Korean in all other States. In 1980, all four categories appeared on the questionnaire. As a result of the additions, the 1980 questionnaire had 14 specific race categories instead of 8 as in 1970.

In 1970, persons who did not report a specific race but wrote in Hispanic categories such as "Mexican," "Puerto Rican," or "Cuban" in the race question were assigned to White; for 1980 these persons remain in the "Other races" category.

See also: "Ancestry;" "Race of Householder;" "Spanish Origin".

Race of Householder
In all cases where occupied housing units, households, or families are classified by race, the race of the householder, i.e., the person in column 1, is used (see Household Relationship for the definition of Householder). This item was determined on a complete-count basis.

Since some households include persons of more than one race, there may be minor differences in counts by race between (1) tabulations of "families by family size" or "households by persons in unit" where all persons regardless of their race are tallied according to tile race Of householder and (2) tabulations of "persons in families" or "persons in households" where all persons are counted according to their own race.

Historical comparability
Prior to 1980, the concept of race of household head" was used instead of race of householder. (See tile historical comparability for Household Relationship.) This change should not substantively affect the comparability of these data.

Real Estate Taxes
See "Owner Costs, Selected Monthly".

Region (Census Geographic)
A large group of States, which is a first-order subdivision of the United States for census purposes. The four regions--Northeast, North Central, South, and West-are delineated in figure 6. Regions are identified by a l-digit code. Statistics for them appear in U.S. Summary reports in almost every publication series, and in STF's lC, 2C, 3C, and 4C. The census regions have no relationship to the 10 Standard Federal Administrative Regions.

Related Children
See "Household Relationship".

Rental Vacancy Rate
The number of vacant units for rent as a percent of the total rental inventory--that is, all renter-occupied units and all year-round vacant units for rent. Vacant units that are seasonal or held off the market are excluded.

See also: "Vacancy Status".

Rent, Contract
The monthly rent agreed to, or contracted for regardless of any furnishings, utilities, or services that say be included. Rent is shown for occupied units rented for cash and vacant units for rent. For vacant units, rent is the amount for the asked unit at the time of enumeration, and is sometimes labeled "rent asked." Contract rent is tabulated for "specified renter occupied" units, which excludes one-family houses on 10 acres or more. Respondents were to report rent only for the housing unit enumerated and to exclude any rent paid for additional units or for business premises. The rent amount for the unit is to be reported even if paid for by someone outside the household, or for some reason, not paid. Respondents who do not pay rent monthly are asked to convert the sum to a monthly average. In the computation of aggregate and mean rent, $35 is taken as the average of the interval "less than $50," and $550 is taken as the average of the interval "$500 or more." This item was asked on a complete-count basis.

No cash rent
Rental units occupied without payment of cash rent. Next may be owned by friends or relatives who live elsewhere and who allow occupancy without charge. Rent-free houses or apartments may be provided to compensate caretakers, ministers, tenant farmers, sharecroppers, or others.

Historical comparability
Similar data have been collected since 1930 (although the first full housing census did not occur until 1940). Rent intervals reported have gone to higher dollar figures in recent decades. The 1970 question on rent had a top category of $300 or more; it also listed fewer rent intervals than the 1980 question. Constant dollar comparisons, 1979 to 1980, are not prepared.

See also: "Rent, Gross".

Renters
See "Tenure".

Rent, Gross
Contract rent plus the estimated average monthly cost of utilities (water, electricity, gas) and fuels (oil, coal, kerosene, wood, etc.)to the extent that these are paid for by the renter (or paid for by a relative, welfare agency, or friend) in addition to the rent. Gross rent is calculated for "specified renter-occupied" housing units, which excludes one-family houses on 10 acres or mops. Gross rent is sometimes preferred to contract rent in comparing costs since contract rent may or may not include utilities.

While public-use microdata show gross rent in dollar amounts (up to $l, 000), the data are not that precise. One reason is that the basic component, contract rent, is reported by the respondent in terms of intervals. To calculate gross rent, the respondent report is converted to a dollar amount by taking the midpoint of the interval; for example, $55 is used for the interval "$50 to $59" ($35 is taken as the value for "less than $50"; $550 is taken as the value for "$500 or more"). To that figure is added the reported average monthly cost of electricity and gas, and one-twelfth of the reported yearly cost of water and fuels. Gross rent data are typically tabulated in the same intervals as are used for contract rent. A unit classified as "no cash rent" in contract rent is also classified that way in gross rent, even if the unit's occupants pay for utilities themselves. Gross rent is calculated on a sample basis.

Gross rent as a percentage of income
The ratio of gross rent to household income in 1979, converted to percentage form, reported for "specified renter-occupied" units, which excludes one-family homes on 10 acres or more. Data are reported as medians and in terms of the number of units in categories such as "less than 20 percent, "20 to 24 percent," "25 to 34 percent," and "35 percent or more" ', and these figures are typically cross-classified with household income. No-cash-rent units and units occupied by households reporting no income or a net loss are assigned to a "not computed" category. This item was computed on a sample basis.

Limitations
In addition to the effect of using interval midpoints, noted above, gross rent data are affected by the tendency of respondents to overstate utility costs.

Historical comparability
Gross rent data have been derived since 1940. In 1970, gross rent figures were somewhat more precise since exact dollar figures were available for contract rent. Also, in reporting a rent-to-income relationship, gross rent was computed as a percentage of family or primary individual income, not household income.

See also: "Energy Costs, Monthly Residential;" "Rent, Contract".

Residence In 1975
The usual place of residence 5 years before the census (i.e., on April 1, 1975), was asked on a sample basis of persons 5 years old or over. If residence was not in "this house" in 1975, the location was recorded in terms of State, county, and city, or foreign country. The same rules for usual place of residence apply to 1975 as to 1980. Persons such as college students or military personnel were to report the actual residence rather than the legal residence, if different. Residence in 1975 is used in conjunction with residence in 1980 to determine the residential mobility of the population.

Same house
All persons 5 years old and over who did not move during the 5 years, plus persons who moved, but by 1980 had returned to their 1975 residence.

Different house in the United States
Persons who lived in the United States on April 1, 1975, in a different house from the one they occupied on April 1, 1980. This includes persons who lived in the same building, but a different apartment, or in the same mobile home but in a different location.

Same county
Persons who lived in a different house in the same county in 1975.

Different county
Persons who lived in a different county.

Same State
Different State
This population is frequently subdivided by region of 1975 residence.

Abroad
Persons with residence in a foreign country, Puerto Rico or an outlying area of the United States in 1975, including Armed Forces stationed overseas.

Certain tabulations (for example, in Census Tracts reports) subdivide the different-house-in-the-United States category in a different way: central city of this SMSA, balance of this SMSA, and outside this SMSA.

Write-in responses were coded in census processing offices for a sample of approximately one-half of all long-form questionnaires (a cost-saving measure). For persons in the United States in 1975, census basic records specify the State, and county, and the city, town, or village (if residence was inside the incorporated limits). In the Northeast region, minor civil division of previous residence is also included on census basic records. For persons abroad in 1975, the basic records specify the country or outlying area. Public-use microdata A and "B" samples show residence in 1975 In the same terms as they show 1980 residence, that is, States, SMSA'S, selected places and county groups with 100,000 or more inhabitants. This makes possible the tabulation of a full origin-destination matrix of migration flows. The "C" sample shows residence in 1975 in terms of regions, divisions and selected States.

Subject reports are planned to cross-tabulate State of residence in 1975 with State of residence in 1980.

Certain tabulations present data on residence in 1975 separately for persons who were in the Armed Forces or in college in 1975 or 1980 so that their movements can be discounted in assessing migration trends.

The number of persons living in a different house in 1975 is less than the total number of changes in residence during the 5-year period. Some persons in the same house at the two dates had moved during the 5-year period but by the time of enumeration had returned to their 1975 residence. Other persons who were living in a different house had made two or more intermediate moves.

Limitations
Since Residence In 1975 was coded for only a half sample of the long-form questionnaires, rather than the full sample, and cross-tabulation involving residence in 1975 (e.g., by age) will yield estimates which differ somewhat from figures derived from the full sample or the complete count. For example, the estimated number of persons 5 years old and over derivable from residence-in-1975 tabulations will not be exactly the same as found in other age tabulations.

Historical comparability
Similar questions on residence 5 years earlier were asked in 1940, 1960, and 1970. The mobility question in 1950 applied to residence one year earlier. Prior to 1980, publications included the category Moved. Residence Not Reported. In 1980, allocations have been made for nonresponse.

See also: "Nativity And Place of Birth;" "Year Moved into Unit".

Residential Energy Costs
See" Energy Costs, Monthly Residential".

The number of whole rooms intended for living purposes, not only in occupied housing units, but also in vacant units. These rooms include living rooms, dining rooms, kitchens, bedrooms, finished recreation rooms, enclosed porches suitable for year-round use, and lodger's rooms. Excluded are strip or pullman kitchens, bathrooms, open porches, balconies, foyers, halls, half-rooms, utility rooms, unfinished attics or basements, or other space used for storage. A partially divided room, such as a dinette next to a kitchen or living room, is a separate room only if there is a partition from floor to ceiling, but not if the partition consists solely of shelves or cabinets. This item was asked on a complete-count basis.

In the computation of aggregate and mean rooms, 10 is taken as the average of the interval "9 or more rooms."

Historical comparability
Similar data have been collected since 1940.

See also: "Bathrooms;" "Bedrooms;" "Persons per Room".

See "Urban and Rural (Population)".

Rural Farm
See "Farm Residence".

Rural Nonfarm
See "Farm Residence".

Sale Price Asked
See "Value".

School Enrollment
Persons 3 years old or over are classified as enrolled in school if they attended regular school or college at any time since February 1, 1980. This question was asked on a sample basis.

Schooling included
As indicated on the questionnaire and in instructions to respondents, regular school or college includes nursery school, kindergarten, elementary school and schooling which leads to a high school diploma or college degree. Attendance can be either by day or night, full time or part time, to be counted as regular schooling. Enrollment in a trade or business school, company training, or tutoring was counted if the course would be accepted for credit at a regular elementary school, high school, or college.

Schooling excluded
Persons were excluded from the enrollment figures if the only schools they bad been attending at any time since February 1, 1980, were not "regular" (unless courses taken at such schools could have been counted for credit at a regular school). Schools regarded as not "regular" may include nursery schools which simply provide custodial day care; specialized vocational, trade, or business schools outside the "regular" system, such as television repair schools, barber's colleges, or typist's training schools; on-the-job training; and correspondence courses.

Historical comparability
Questions on schooling have been included since 1930, although the time reference varied until 1950 when February 1 to the time of enumeration was adopted as the reference period. Most tabulations of school enrollment in 1970 were restricted to persons 3 to 34 years old, whereas most 1980 tabulations do not have an upper age limit.

See also: "School Level;" "School Type;" "School Years Completed".

School Level
Persons 3 years old and over enrolled in regular school (see School Enrollment) are classified according to the level and year of school in which they were enrolled. This information was collected on the sample questionnaire by means of a question which asked for the highest grade or year attended.

Respondents were instructed to report the highest grade attended even if it was not completed. Persons still in school were to mark the grade in which they were currently enrolled. Schooling received in ungraded schools was to be reported as the equivalent grade in the regular American school system.

Nursery school
A school organized to provide educational experiences for children during the year or years preceding kindergarten. Children in "Head Start" or similar programs were to be reported in nursery or kindergarten as appropriate; if the respondent was uncertain as to the level of the Head Start Program, nursery school was to be marked.

Kindergarten
An organized educational program the year before first grade.

Elementary school
Includes grades 1 through 8, identified separately in some tabulations. (Persons enrolled in a junior high school or middle school are classified as enrolled in elementary school or high school according to year in which enrolled.)

High school
Includes grades 9 through 12, identified separately in some tabulations.

College
Junior or community colleges, regular 4-year colleges, and graduate or professional school. Includes 1 through 7 academic years and 8 years or more, identified separately in some tabulations.

Entries on highest grade attended were edited for consistency with age. For instance, entries indicating college attendance for persons under 15 years old were edited out.

Historical comparability
Nursery school first appeared as a category in 1970. An item on vocational training which was included in the 1970 census, was deleted in 1980. For 1980 as compared to 1970, there was an increase in the number-of-years-of-college categories, from "6 or more" to "8 or more."

See also: "School Enrollment;" "School Type;" "School Year Completed".

School Type
Persons 3 years old and over enrolled in regular school (see School Enrollment) are classified according to whether they are attending public, private church-related, or other private schools. This information is collected on a sample basis. In using the public/private school distinction for college enrollment, some caution should be exercised since there is evidence that in some parts of the country, the classification of individual schools may not be entirely clear and census data may differ considerably from administrative figures.

Public
Any school or college which is controlled and supported primarily by a local, county, State, or Federal government.

Church related
A nonpublic school or college which is controlled and supported primarily by a religious organization, e.g., a parochial school. (Respondents were not instructed how to distinguish private church-related from private, not church-related schools.)

Other private
A nonpublic school or college controlled or supported primarily by private groups other than religious organizations; such as private nursery schools and nonreligious elementary schools.

Historical comparability
Similar to a question asked in 1970, but with the following wording modifications: the 1970 questionnaire category "Yes, public" was changed to "yes, public school, public college"; "yes, parochial" was changed to "yes, private, church-related"; and "yes, other private" was changed to "yes, private, not church-related."

See also: "School Enrollment;" "School Level".

School Years Completed
Data on years of school completed are derived from two questions, one identifying the highest grade attended in regular school (see School Enrollment); the second determining whether the respondent finished the grade specified. These data were collected on a sample basis.

Those persons who passed a high school equivalency examination (such as GED) were marked "12" under the highest grade attended (if they had not completed or were not enrolled in a higher grade). Schooling received in foreign schools was to be reported as the equivalent grade or year in the regular American school system.

The number tabulated in each category of years of school completed includes (a) persons who reported that they had attended the indicated grade and had finished it, (b) those who had attended but did not complete the next higher grade and (c) those still attending the next higher grade. Most tabulations of years of school completed are restricted to persons 25 years old and over, although some include persons 18 to 24 years old. Tabulations include persons in school as well as those who have completed their schooling. A typical way of reporting years of school completed is as follows:

Elementary:
       0 to 4 years
       5 to 7 years
       8 years

High School:
       1 to 3 years
       4 years

College:
       1 to 3 years
       4 or more years

High school graduates
Persons who have completed 4 years of high school (grade 12) or any higher level of education. Therefore, to obtain a count of high school graduates from the breakdown illustrated above, the categories "High school: 4 years, "College: 1 to 3 years," and "College: 4 or more years" are to be ridded together.

Median school years completed
Calculated as divides the value which the population in half. Years-of-school-completed statistics are converted into a continuous series: the first year of high school becomes grade 9, the first year of college, grade 13, etc. Persons who have completed a given year are assumed to be evenly distributed from .O to .9 of the year. For example, persons rho have completed the 12th grade are assumed to be evenly distributed between 12.0 and 12.9. Note that this assumption is different than that applicable to other discrete variables. Actually, at the time of enumeration, most of the enrolled persons had attended at least three-fourths of a school year beyond the highest grade completed, whereas a large majority of persons who were not enrolled had not attended any part of a grade beyond the highest one completed. The effect of the assumption is to place the median for younger persons slightly below, and for older persons, slightly above, the true median.

Historical comparability
Questions on years of school completed have been asked in censuses since 1940, as a replacement for the literacy question which had been asked from 1840 to 1930.

See also: "School Enrollment;" "School Level".

Seasonal and Migratory Vacant Units
See "Vacancy Status".

Sewage Disposal
The type of sewage disposal system for the structure in which the unit is located, ascertained for occupied and vacant housing units. This item was asked on a sample basis.

Public sewer
Connected to a city, county, sanitary district, neighborhood, or subdivision sewer system. A public sewer may be operated by a government body or by a private organization. Small sewage treatment plants, called "neighborhood septic tanks" in some localities, are classified as public sewers. All units in structures with five or more units are assumed to be connected to a public sewer if the unit has running water.

Septic tank op cesspool
An underground tank or pit into which sewage flows from the plumbing fixtures in the building.

Other means
Includes an individual sewer line running to a creek, lake, swamp, etc.; units with a privy; and other arrangements.

Historical comparability
Similar data were collected in 1960 and 1970; in 1960, however, data were collected only outside cities with 50,000 or more persons.

See also: Bathroom: Complete Bathroom; Plumbing Facilities; Water; Source Of

Ascertained on a complete-count basis.

Historical comparability
A question on the sex of individuals has been asked of the total population in every census.

Single-Family Homes
See "Units in Structure".

Size of Household
See "Household, Persons In".

Size of Housing Unit
See "Rooms".

Size of Structure
See "Units in Structure".

Source of Water
See "Water, Source Of".

Spanish Origin
Determined by a complete-count question which asks respondents to self-identify whether they are of Spanish origin or descent. If, when interviewed, the person reported a multiple origin and could not provide a single origin, the origin of the person's mother was used. If a single response was not provided for the person's mother, the first reported origin of the person was used.

Counts of the population by Spanish origin in complete-count tabulations are provisional. Final counts for Spanish origin will be determined after the sample data have been processed. The sample counts will first appear on the tape in STF 3 and in print in Characteristics of Population, General Social and Economic Characteristics, PC80-1-C reports.

Persons marking any one of the four "Spanish" categories, i.e., Mexican, Puerto Rican, Cuban, or other Spanish, are collectively referred to as "persons of Spanish origin."

In certain tabulations, persons of Spanish origin are further classified by type:

Mexican
Persons who indicated "Mexican, Mexican-American, Chicano," or wrote in an entry such as "La Raza."

Puerto Rican
Persons who indicated "Puerto Rican" or wrote in an entry such as "Boricua."

Persons who indicated "Cuban."

Other Spanish
Persons who filled the circle for "other Spanish/Hispanic"; or persons who wrote in an origin or descent associated with Spain, the Dominican Republic, or any Central or South America country except Brazil or a nonspecific Spanish group such as "Spanish surnamed" or "Spanish speaking."

Preliminary evaluations of 1980 census data suggest some limited misreporting of Spanish origin.
Available evidence indicates that the misreporting mw have occurred only in selected areas with relatively small Spanish-origin populations, such as in some Southern States, but it is not apparent in those areas with the largest concentrations of Spanish-origin persons. For a fuller discussion of the reporting in the Spanish-origin item, see the forthcoming 1980 census Supplementary Report, "Persons of Spanish Origin by State: 1980" (PC80-Sl).

Historical comparability
The Spanish-origin question was asked on a l00-percent basis for the first time in 1980. A similar question was asked on the 1970 5-percent sample questionnaire. For 1980, the category "No, not Spanish/Hispanic" appeared first (the corresponding category appeared last in 1970). Also, the terms "Mexican-American" and "Chicano" are added to the term "Mexican." The category "Central or South American," included in 1970, was dropped.

Although a question on Spanish origin was included in 1970, it was not the major identifier used to classify the Hispanic population in the 1970 census as it is in 1980. Depending on the section of the country, 1970 census data for "Persons of Spanish Heritage" were variously defined as "Persons of Puerto Rican Birth or Parentage" (in New York, New Jersey, and Pennsylvania), as "Persons of Spanish language or Spanish Surname" (in Arizona, California, Colorado, New Mexico, and Texas), and as "Persons of Spanish Language" (in the remaining 42 States and the District of Columbia). "Spanish Language" referred to those persons who in 1970 reported Spanish as their mother tongue, as well as persons in families in which the household head or spouse reported Spanish as his or her mother tongue.

Spouse
See "Household Relationship".

Standard Consolidated Statistical Area (SCSA)
A large concentration of metropolitan population composed of two or more contiguous standard metropolitan statistical areas (SMSA's) which together meet certain criteria of population size, urban character, social and economic integration, and/or contiguity of urbanized areas. Each SCSA must have a population of one million or more. Thirteen SCSA'S were in existence at the time of the 1980 census. They were defined by the Office of Management and Budget according to criteria published by that office in Standard Metropolitan Statistical Areas: 1975. Four additional SCSA's have been defined based on 1980 census results.

SCSA'S are identified by a 2-digit numeric code. Summaries for SCSA's appear in many reports, and in STF's lC, 2C, 3C, and 4C. Summaries are generally provided for SCSA totals and for within-State parts of SCSA's.

Historical comparability
The original 13 SCSA's were designated in 1975. For the 1960 and 1970 censuses, the Census Bureau recognized two "Standard Consolidated Areas" (SCA's), which encompassed metropolitan complexes around New York and Chicago.

In 1982 or 1983, the SCSA concept will be replaced by the new Consolidated Metropolitan Statistical Area (SMSA) concept, with somewhat more flexible criteria, as spelled out in the Federal Register, January 3, 1980. These changes will not affect publication of l980 census data for SCSA's.

Standard Metropolitan Statistical Area (SMSA)
A large population nucleus and nearby communities which have a high degree of economic and social integration with that nucleus. Each SMSA consists of one or more entire counties (or county equivalents) that meet specified standards pertaining to population, commuting ties, and metropolitan character. In New England, towns and cities, rather than counties, are the basic units and should be substituted for "counties" where counties are cited below. SMSA's are designated by the Office of Management and Budget.

Data products from the 1980 census will report on 323 SMSA's:

(1) 287 defined before January 1, 1980 (including 4 in Puerto Rico); and
(2) an additional 36 (including one in Puerto Rico) established as a result of 1980 census population counts. The 36 new SMSAs were designated when 1980 counts showed that they met one or both of the following criteria:

1.Included a city with a population of at least 50,000 within its corporate limits, or
2.Included a Census Bureau-defined urbanized area (which must have a population of at least 50,000) and a total SMSA population of at least 100,000 (or, in New England, 75,000).

An SMSA includes a city and, generally, its entire UA and the remainder of the county or counties in which the UA is located. An SMSA also includes such additional outlying counties which meet specified criteria relating to metropolitan character and level of commuting of workers into the central city or counties. Specific criteria governing the definition of SMSA's recognized before 1980 are published in Standard Metropolitan Statistical Areas: 1975, issued by the Office of Management and Budget.

With two exceptions, each SMSA has one or more central cities, up to a maximum of three, and the names of these cities form the title of the SMSA. The Nassau-Suffolk, NY, SMSA has no central city, and the title of the Northeast Pennsylvania SMSA does not contain the names of its three central cities: Scranton, Wilkes-Barre, and Hazleton.

SMSA's are identified by a FIPS 4-digit numeric code, which follows the alphabetic sequence of SMSA names. SMSA's are outlined on small scale maps in several 1980 report series. SMSA data appear in most 1980 census publications and summary tape files. Many SMSA's cross State boundaries, and reports in several series provide summaries for the State parts of multi-State SMSA s, as well as SUSA totals. Summary tape files present data only for State parts of SMSA's, except for the "national" files: STF's lC, 2C, 3C, and 4C.

Historical comparability
A comparison of 1970 and 1980 census products reveals two types of changes in metropolitan territory. First, 69 new SMSAs were created from previously nonmetropolitan territory: 36 were defined in 1981 based on 1980 population counts and 33 were defined between 1973 and 1979 based on current population estimates. (An additional SMSA--Rapid City, SD--was provisionally recognized based on population estimates, but it did not qualify according to 1980 census data.)

The second component of change to metropolitan territory between 1970 and 1980 was the redefinition of many of the SMSA's which were recognized in 1970 census tabulations. Of the 247 1970 SMSA's, 101 were redefined in 1973 based on 1970 census commuting data, most by the addition of 1 or more counties (or towns and cities in New England). In addition, one SMSA was redefined by the addition of one area and the deletion of another (Wichita Falls, Texas), one was subdivided (Nassau-Suffolk SMSA was created from a part of the New York SMSA), four pairs of SMSA's were combined into single SMSA'S (for example, Dallas-Fort Worth, Texas), and four SMSA's lost area that was added to other SMSA's. In addition, the names of several SMSA's were changed in 1973, one in such a way that the SMSA code also changed (San Bernardino-Riverside-Ontario to Riverside-San Bernardino-Ontario, California).

Since SMSA's are always defined in terms of whole counties (towns or cities in New England) for which extensive data are available, users can usually compile figures for comparisons over time.

In 1982 or 1983, SMSA boundaries will be reevaluated using 1980 census data on commuting, labor force, population density, type of residence, and population growth, according to new criteria spelled out in the Federal Register, January 3, 1980 (vol. 45, no. 2, pt. VI). At that time, new outlying counties may be added or existing ones deleted, some area titles will be changed and new central cities designated, some areas may be consolidated, and a few new SMSA's may be created. Further, the term "standard metropolitan statistical area" will be shortened to "metropolitan statistical area" (MSA). These changes will not affect publication of for SMSA's.

A major political unit of the United States. The District of Columbia is treated as a State-equivalent in all 1980 census data series. Puerto Rico is also, except that it does not appear in P.L. 94-171 Population Counts file. American Samoa, Guam, Northern Mariana Islands, the remainder of the Trust Territory of the Pacific Islands, and the U.S. Virgin Islands are treated as State equivalents for the presentation of data in 1980 population and housing volume 1 reports, but data for these areas will be available on computer tape only on STF's 1 and 3.

States are identified by a 2-digit FIPS code which follows the alphabetic sequence of State names (including the District of Columbia), and by a 2-digit census geographic State code, the first digit of which identifies the census division of which the State is a part. Puerto Rico and the outlying areas have FIPS codes numerically following the State codes.

Historical comparability
There have been no significant changes to State boundaries in the last decade. Data for the Northern Mariana Islands are reported separate from remainder of the Trust Territory for the 1980 census.

See also: "Puerto Rico and Outlying Areas".

State Economic Area (SEA)
A single county or group of counties within a State which is relatively homogeneous with respect to economic and social characteristics. The grouping of the 3,103 counties and county equivalents in 1950 into SEA's was the product of a special study prepared by the Bureau of the Census in cooperation with the Bureau of Agricultural Economics and several State and private agencies. Boundaries were drawn in such a manner that each economic area had certain significant characteristics which distinguished it from adjoining areas. There are 510 SEA's.

SEA's are identified in census tabulations on computer tape by a 2- digit numeric code or a 1-digit alphabetic code, assigned sequentially within the State; however, no 1980 data are summarized for SEA's.

Historical comparability
SEA boundaries have remained largely unchanged since they were defined in 1950. In 1950, 501 areas were defined; in 1960, 509; and in 1970, 510.

See also: "Economic Subregion".

State of Birth
Persons born in the United States were asked to report their State of birth as the State where the person's mother was living at the time the person was horn (not the location of the hospital if in a different State). This item was asked on a sample basis.

Specific States were coded from the write-in entries in census processing offices. Specific codes are assigned for each State and for Puerto Rico and outlying areas of the United States, including Virgin Islands, American Samoa, and Guam. ' dost presentations are limited to the following:

Born in State of residence

Born in different State:

       Northeast

       North Central

       South

       West

Born abroad, at sea, etc.

Specific States of birth will be published only in a subject report, but will be available on basic records and public-use microdata.

Historical comparability
The format of the place-of-birth question was changed from 1970 so that the instruction to enter the State where the person's mother was living at the time the person was born is highlighted so that respondents would not report the location of the hospital if in a different state from the mother's usual residence.

See also: "Country of Birth;" "Nativity and Place of Birth".

Stories in Structure
The number of stories or floors in the building in which the unit is located, ascertained for occupied and vacant units. Stories (or floors) include basements or attics if these contain finished rooms for living purposes. (A basement is an enclosed space in which a person can walk upright under all or part of the building.) This item was asked on a sample basis.

Responses for stories in structure were edited for consistency with information on units in structure. The responses given for units in structures with fewer than 5 units were edited to "1 to 3" stories.

Historical comparability
Similar data have been collected since 1960; in 1960, however, data were collected only in cities with 50,000 or more inhabitants. In 1980, basements finished for living purposes were counted as stories for the first time.

See also: "Elevator in Structure".

Structural Characteristics
See "Elevator in Structure;" "Stories in Stucture;" "Units in Structure;" "Year Structure Built".

Subfamily Type
See "Family".

Taxes on Real Estates
See "Owner Costs, Selected Monthly".

Telephone in Unit
Presence of a telephone in the housing unit, ascertained for occupied units. A telephone in the building but not in the respondent's living quarters is not counted. This item was asked on a sample basis.

Historical comparability
Similar data have been collected since 1960. The 1980 question differs from its 1970 and 1960 counterpart which, designed more as an aid to enumeration, asked whether the household could be reached by phone. The 1980 question refers only to a telephone inside the housing unit. (As an aid to follow up enumeration, respondents were also asked to write their telephone numbers on the back of the questionnaire.)

Tenure
The classification of all occupied housing units as either owner-occupied or renter-occupied. This item was asked on a complete-count basis.

Owner-occupied
A housing unit is "owner occupied" if the owner or co-owner lives in the unit even if the unit is mortgaged or not fully paid for. The owner or co-owner must live in the unit but need not be the person listed in column 1 of the 1980 census questionnaire.

Renter-occupied
All occupied housing units which are not owner occupied, regardless of whether cash rent is paid by a member of the household. ("No cash rent" units, a subcategory of renter occupied, are separately identified in rent tabulations. Such units are generally one provided free by friends or relatives, or in exchange for the services of, for example, a caretaker, minister, tenant farmer, or sharecropoer.)

Historical comparability
Tenure has been collected since 1890. In 1970, the question on tenure also included a category for condominium and cooperative ownership. In 1980, condominiums are identified in a separate question.

See also: "Condominium Status;" "Owner Costs, Selected Monthly;" "Rent, Contract;" "Rent, Gross;" "Value".

Town/Township
See "Minor Civil Division".

See "Census Tract".

Trailers
See "Units at Address;" "Units in Structure".

Transportation to Work, Means Of
The principal means of travel or type of conveyance usually used during the reference week in traveling from home to work at the address give" in the place-of-work question. (The reference week was the calendar week prior to the date on which the respondent or enumerator completed the questionnaire, further discussed under Labor Force Status.) If more than one means of transportation was used, the respondent was instructed to report the one usually used for most of the distance. These data were obtained from the full sample for persons at work last week (i.e., including both civilian employed and Armed Forces at work) and are tabulated for persons 1B years old and over.

Major categories which appear in abbreviated tabulations include:

Private vehicle
Cars (including station wagons and company cars), trucks (including pickup trucks and small panel trucks); and vans with passenger seats and side and/or rear windows.

Drive alone
Includes persons who usually drove alone as well as persons who were driven to work by someone who then drove back home or to a nonwork destination.

Carpool
Persons who share driving (e.g., person in carpools who took turns driving on different days), drive others only, or ride as a passenger only (includes persons who were usually driven to work by another worker, not necessarily someone who worked at the same place PS the respondent). Persons in a carp001 were also asked how many people usually rode to work in the car, truck, or van (see Vehicle Occupancy).

Public transportation
Buses or streetcars, railroads (including commuter trains), subway or elevated (rapid transit operating on its own right-of-way underground, on the surface, or elevated), and taxicab.

Other means
Motorcycles, bicycles, write-in responses (e.g., ferryboat, airplane), and persons who "walked only," i.e., who walked to work and used no other means of transportation.

Worked at home
Persons working on a farm where he or she lived, or in an office or shop in the person's house.

Note that a respondent who was on a business trip during the reference week may report a means of transportation to work that does not seem reasonable for the place of residence, e.g., a resident of Montana reporting going to work last week by subway. There was no coding of write-in responses within the "other means" category.

Historical comparability
Data on means of transportation to work have been collected since 1960. In 1970, the question referred to the means of transportation to work on the last day of the previous week rather than the usual means during the week. The categories for trucks, vans, motorcycles, and bicycles are new for 1980. Rather than using a separate question on carpooling, the 1970 means-of-transportation-to-work question specified "driver, private auto" and "passenger, private auto."

See also: "Place of Work;" "Travel Time to Work;" "Vehicle Occupancy to Work".

Travel Time to Work
The usual number of minutes spent in traveling from home to work (one way) during the reference week, ascertained for persons at work last week and tabulated for persons 16 years old and over. (See the discussion of the reference week under Labor Force Status.) Travel time includes time spent waiting for public transportation, picking up passengers in carpools, etc. Time taken occasionally to stop for meals, shopping, appointments, taking children to school, etc. was not included. This item was asked on a sample basis.

This item was coded in census processing offices from the respondent's write-in entry and is recorded on census basic records and public-use microdata in minutes. In some reports, travel time to work is reported in terms of categories: less than 10 minutes, 10 to 19 minutes, 20 to 29 minutes, 30 to 44 minutes, and 45 or more minutes. More frequently the data are presented as an average: mean travel time to work, reported in minutes.

Limitations
Since travel time to work was coded only for a sample of one-half of all long-form questionnaires, along with place of work and residence in 1975. The estimated number of workers 16 years and over who did not work at home as derived from travel time figures will differ somewhat from the corresponding figure derived from a tabulation of means of transportation to work, a full-sample item. Further, any cross-tabulation of travel time to work with other items is necessarily based only on the half sample.

Historical comparability
Travel time to work is a new item for 1980.

See also: "Place of Work;" "Transportation to Work, Means Of;" "Vehicle Occupancy".

Trucks or Vans Available
The number of vans, pickups, and small panel trucks of one-ton capacity or less which are owned or regularly used by any member of the household and which are ordinarily kept at home. Company vans and trucks of one-ton capacity or less are also included if kept at home by a household member and used for nonbusiness purposes. Vans and trucks kept at home are not included if used only for business purposes. The statistics, therefore, do not reflect the number of privately owned trucks or vans or the number of households owning such vehicles. The statistics are ascertained for occupied housing units. This item was asked on a sample basis.

Limitations
A test survey taken before the census showed that the percent of households with several vans or trucks was understated, and the percent of households with "no vans or trucks" was overstated, when compared to the results of reinterviews.

Historical comparability
This question has not been asked in a census before.

See also: "Automobiles Available".

Type of Structure
See "Units in Structure".

United States
This designation includes the 50 States and the District of Columbia. 1980 STF's and most report series (usually in a separate U.S. Summary report) provide data summarized for the United States.

Unit, Persons In
See "Household, Persons In".

Units at Address
Number of housing units with a particular house or building address number. This question is asked principally to improve census coverage. If the respondent indicated from 2 to 9 units at the address, census workers checked the number against the number of units for that address on the Bureau's address register. If the respondent's answer was higher than what WIBS shown in the address register, the building was visited to ascertain the correct number of units, thereby assuring enumeration of every unit. This item was asked on a complete-count basis.

Mobile home or trailer
Included if intended for occupancy where located. Mobile homes or trailers were counted whether mounted or on wheels.

Limitations
Data users sometimes use "units at address" as a proxy for "units in structure," which is published later because it is based on a sample question. The concepts are not interchangeable, though, since some multi-unit buildings have more than one address and there is some variation in respondent interpretation of "units at address."

Historical comparability
Similar data were collected in 1970.

See also: "Units in Structure".

Units in Structure
The number of housing units in the structure in which the unit is located. The number of units in structure includes all housing units whether occupied or vacant, but excludes group quarters or businesses. The statistics are presented in terms of the number of housing units in structures of specified types and sizes, not in terms of the number of structures.

A structure is a separate building that either has open space on all sides or is separated from other structures by dividing walls that extend from ground to roof. This was determined on a sample basis.

One-family house
Synonymous with 1-unit structure (i.e., the term does not imply occupancy by a family as defined for census purposes). This category excludes mobile homes or trailers as defined below.

1-unit, detached
1-unit structure detached from any other house, i.e., with open space on all four sides. Such structures are considered detached even if they have an adjoining shed or garage. A one-family house which contains a business is considered detached as long as the building has open space on all four sides. Mobile homes or trailers to which one or more permanent rooms have been added or built on are also included.

1-unit, attached
1-unit structure which has one or more walls extending from ground to roof separating it from adjoining structures. In row houses (sometimes called townhouses), double houses, or houses attached to nonresidential structures, each house is a separate attached structure if the dividing or common wall goes from ground to roof.

2-or-more units
Units in structures containing 2 or more housing units; further categorized as units in structures with 2, 3 or 4, 5 to 9, 10 to 19, 20 to 49, and 50 or more units.

Mobile home or trailer, etc
Both occupied and vacant mobile homes to which permanent rooms have been added. If only a porch or shed has been added, the unit is counted in this category. Note that mobile homes or trailers used only for business purposes or for extra sleeping space, and mobile homes or trailers for sale on a dealer's lot at the factory, or in storage are not counted in the housing inventory. In the printed reports, this category includes occupied housing units indicated as "boat, tent, van, etc.," i.e., any occupied units which do not fit the other listed categories. Houseboats, railroad cars, campers, and caves used as a usual place of residence provide additional examples.

Limitations
Users of small-area data occasionally are troubled by certain anomalies in units-in-structure data. For example, a user may encounter a table in which only 5 units in a census tract are listed as being in a structure of 10 or more units. Sometimes respondents do not know the exact number of units in a structure and give an incorrect response.

Historical comparability
Data have been collected on units in structure since 1940 and on mobile homes and trailers since 1950.

The residual category "boat, tent, van, etc." replaces the 1970 category "other--describe." The instruction to respondents that a mobile home or trailer counts as a detached house if a room (though not a porch or shed) has been built on to it was added in 1970 and retained for 1980.

See also: "Units at Address".

Unmarried Couples
Households consisting of two unrelated persons 15 years old and over of opposite sex, regardless of their marital status, and regardless of the presence or absence of persons under 15; derived from responses to household relationship, sex, and age questions. Data are presented only in limited tabulations in PC80-l-D and STF 5. This item was derived on a sample basis.

Historical comparability
This is a new concept for census publications. It could, however, also be applied to microdata from earlier censuses.

Unrelated Individual
An unrelated individual may be (1) a householder living alone or only with persons not related to him or her, (2) a roomer, boarder, partner, roommate, or resident employee unrelated to the householder, or (3) a group quarters member who is not an inmate of *n institution. Classification as an unrelated individual derives from the complete-count question on household relationship. Examples of unrelated individuals include a widow who occupies her house alone or with one or more other persons not related to her, a roomer not related to the householder, a maid living as a member of her employer's household, and a resident staff member in a hospital dormitory. Persons living with one or more relatives in 8 household where the householder is not related to any of them are classified in the census as unrelated individuals; for example, a husband and wife who rent a room from a householder to whom they are not related.

Presentations are shown for the universe of "unrelated individuals 15 years and over" for income and poverty.

Historical comparability
A similar concept was used in 1970.

See also: "Family;" "Household Relationship".

Urban and Rural (Population)
Urban and rural are type-of-area concepts rather than specific areas outlined on maps. As defined by the Census Bureau, the urban population comprises all persons living in urbanized areas (UA's) and in places of 2,500 or more inhabitants outside UA's.

The rural population consists of everyone else. Therefore, a rural classification need not imply farm residence or a sparsely settled area, since a small city or town is rural as long as it is outside a UA and has fewer than 2.500 inhabitants.

The terms urban and rural are independent of metropolitan and nonmetropolitan designations; both urban and rural areas occur inside and outside SMSA's.

Historical comparability
Except for the minor relaxation of UA criteria discussed below, urban and rural definitions have been consistent since 1950. Within small counties, measurements of urban and rural populations over time may he significantly affected by the increase or decrease of a place's population across the 2,500 population threshold, e.g., the increase of 1 person to a place of 2,499 results in an increase of 2,500 to the county's urban population.

Urban Fringe
See "Urbanized Area".

Urbanized Area (UA)
A population concentration of at least 50,000 inhabitants, generally consisting of a central city and the surrounding, closely settled contiguous territory (suburbs).

The UA criteria define a boundary based primarily on a population density of at least 1,000 persons per square mile, hut also include some less densely settled areas, and such areas as industrial parks and railroad yards, if they are within areas of dense urban development. The density level of 1,000 persons per square mile corresponds approximately to the continuously built-up areas around a city (ies). The "urban fringe" is that part of the UA outside of a central city (ies).

Typically, an entire UA is included within an SMSA. The SMSA is usually much larger in terms of territory covered and includes territory where the population density is less than 1,000. Occasionally, more than one UA is located within an SMSA. In some cases a small part of a UA may extend beyond an SMSA boundary or possibly into an adjacent SMSA. A few 1980 UA's have been defined in areas: which do not meet the criteria for SMSA designation. UA's may cross State boundaries. In a few cases, a UA does not include all of an "extended city," that is, a place which is determined to have a significant amount of rural territory.

UA's are identified by 4-digit codes, which follow the alphabetic sequence of all UA names. When a UA has the same name as an SMSA, the UA code is usually the same as the SMSA code. UA boundaries are shown on final MMS/VMS maps, and at a much smaller scale on UA outline maps in PC80-1-A and HC80-1-A reports.

Historical comparability
Because UA's are defined on the basis of population distribution at the time of a decennial census, their boundaries tend to change following ee.ch census to include expanding urban development.

The criteria have been fairly constant since 1950, although in each decade some new refinements have been added. For the 1970 census, in which 252 UA's were recognized, it was necessary for the central city to have a population of 50,000 or more, or for there to be "twin cities" with a combined population of 50,000 and with the smaller city having at least 15,000. In 1974 the criteria were liberalized to allow UA recognition to certain cities between 25,000 and 50,000, and this resulted in 27 new urbanized areas. For 1980, no minimum population size is required for a central city.

Utilities
See "Energy Costs, Monthly Residential".

Vacancy, Duration Of
The length of time (in months) from the date the last occupants moved from the unit to the date of enumeration. The data, therefore, do not provide a direct measure of the total length of time units remain vacant. For newly constructed units which have never been occupied, the duration of vacancy is counted from the date construction was completed. For recently converted or merged units, the time is reported from the date conversion or merger was completed. Duration of vacancy was determined for vacant year-round units on a complete-count basis.

Historical comparability
Similar data have been collected since 1960.

See also: "Vacancy Status".

Vacancy Status
Determined for housing units at the time of enumeration. Vacancy status pertains to year-round vacant units. Vacancy status and other characteristics of vacant units are determined by enumerators questioning landlords, owners, neighbors, rental agents, and others.

The housing inventory includes vacant mobile homes or trailers intended to be occupied on the site where they stand. Vacant mobile homes on dealer sales lots or in storage yards are not counted as housing units.

New units not yet occupied are classified as vacant housing units if construction has reached a point where all exterior windows and doors are installed and final usable floors are in place. Vacant units are excluded if open to the elements; that is, if the roof, walls, windows, or doors no longer protect the interior from the elements, or if there is positive evidence (such as a sign on the house or in the block) that the unit is to be demolished or is condemned. Also excluded are quarters being used entirely for nonresidential purposes, such as a store or an office, or quarters used for the storage of business supplies or inventory, machinery, or agricultural products.

Vacant year-round units
Vacant units intended for use, even if only occasionally, throughout the year.

For sale only
Vacant year-round units offered for sale only. The category includes mainly one-family houses, but also two types of vacant units in multi-unit buildings: (1) vacant units (which are for sale only) in a cooperative or condominium and (2) vacant units intended to he occupied by the new building owners in multi-unit buildings that are for sale. 4n individual unit that is vacant because it is being held for sale of the entire building is classified as "other vacant." Vacant units offered for rent or sale at the same time are classified as "for rent."

For rent
Vacant year-round units offered for rent, and vacant units offered for rent or sale at the same time, including vacant units for rent in a building for sale.

Rented or sold, awaiting occupancy
Vacant year-round units sold or rented but still unoccupied when enumerated-- including units where rent is agreed on but not yet paid.

Held for occasional use
Vacant units for weekend or other occasional use throughout the year. Shared ownership or "time sharing" condominiums are also classified here.

Other vacant
Vacant units for year-round occupancy not classified above, for example, units held for a janitor or caretaker, settlement of an estate, pending repairs or modernization, or personal reasons of the owner.

Vacant seasonal and migratory units
Vacant units used or intended for use only in certain seasons. Any unit used throughout the year, even if only occasionally, is excluded. Seasonal units include those used for summer or winter sports or recreation--beach cottages and hunting cabins, for example. Seasonal units may also include quarters for such workers as herders and loggers. Migratory units include those for farm workers during crop season.

Limitations
Most tables exclude vacant seasonal and migratory units since information on characteristics of such units is difficult to obtain.

Historical comparability
Similar data have been collected since 1940. In 1970, seasonal and migratory vacant units were reported in two separate categories.

See also: "Boarded-Up Status;" "Homeowner Vacancy Rate;" "Occupancy Status;" "Rental Vacancy Rate;" "Vacancy, Duration Of".

For owner-occupied housing units, the respondent's estimate of the current dollar worth of the property. For vacant units, value is the price asked for the property. A property is defined as the house and land on which it stands. Respondents estimated the value of house and land even if they only owned the house or owned the property jointly.

Statistics on value are shown only for owner-occupied condominium units and for "specified owner-occupied" units, i.e., one-family houses on less than 10 acres and with no business on the property. Value tabulations exclude renter-occupied units, mobile homes or trailers, houses on 10 or more acres, houses with a commercial establishment or medical office on the property, and noncondominium units in multi-family buildings (e.g., cooperatives).

When value data are presented solely for vacant units for sale only, the term "sale price asked" is substituted. In the computation of aggregate and mean value, $7,500 is taken as the average of the interval "less than $10,000." and $250,000 is taken as the average of the interval "$200,000 or more." This item was asked on a complete-count basis.

Limitations
A 1970 census evaluation study found that respondents tended to report a higher value of home in a reinterview survey, with more detailed questions, than in the census. On the other hand, a comparison of 1970 census reports of value with subsequent actual sale prices of a sample of homes sold one to two years later found that the census understated the median market value of those homes by only three percent (compared to the sale prices adjusted for inflation between the census and sale date). This result cannot be generalized to all census value data, however, since the sample was restricted to metropolitan areas, and since census respondents who were about to sell their homes may have been more aware of market values.

Historical comparability
Similar data have been collected since 1930 (and in 1920 for mortgaged nonfarms only), but value for condominiums is new for 1980. For historical comparability, tables will show condominiums and noncondominiums separately. Values for 1980 reflect increased housing prices: the highest category in 1970 was "$50,000 or more," for 1980, $200,000 or more. Also, the number of categories increased from 11 in 1970 to 24 in 1980.

Vans or Trucks Available
See "Trucks or Vans Available".

Vehicle Occupancy
The number of people, including the respondent, who usually rode together to work in a car, truck, or van during the reference week ("last week"). Riders who rode to school or some other nonwork destination were not included. Vehicle occupancy vas asked on a sample basis for persons at work last week who indicated the use of a car, truck, or van in the means-of transportation-to-work question.

Data are reported in terms of categories like "Drives alone," "In 2- person carpool," "In 3-person carpool." etc., and/or as an average: persons per private vehicle. In the calculation of means or aggregates, 8 is taken as the average value of the open-ended category "7 or more." Note that these data are presented in terms of the number of persons in carpools of a given size, not in terms of the number of vehicles or carpools. To approximate the number of vehicles accounted for by these statistics, divide the number of persons who went to work by car, truck, or van by the mean number of persons per vehicle; to approximate the number of carpools, the subtract number of persons driving alone from the derived number of vehicles.

Historical comparability
New item for 1980.

See also: "Place of Work;" "Transportation to Work, Means Of".

Vehicles Available
The total number of automobiles, vans, and light trucks--one ton or less--available at home for the use of members of the household, ascertained for occupied housing units. This tabulation adds together responses to the two separate questions on automobiles and trucks or vans. "Three or more" vehicles available is the highest category of this question. The statistics do not reflect the number of vehicles privately owned or the number of households owning vehicles. These items were asked on a sample basis.

Historical comparability
Information on vans and light trucks is new for 1980.

See also: "Automobiles Available;" "Trucks or Vans Available;" "Vehicle Occupancy".

Veteran Status and Period of Service
All civilians 16 years and over are classified on the basis of whether they have served in the Armed Forces of the United States, regardless of whether their service was in war or peacetime. This item was asked on a sample basis. (The question was also asked of 15-year-olds and of persons currently in the Armed Forces, but these groups are excluded from the universe of tabulations.)

Veteran
A person who has served but is not currently serving in the Armed Forces of the United States.

Nonveteran
Any other civilian, i.e., a person who has never served in the Armed Forces of the United States.

While the question on period of service allowed responses for more than one time period, these data are tabulated in terms of mutually exclusive categories. If persons served during both wartime and peacetime, they are classified according to the most recent wartime period of service.

  • May 1975 or later
  • Vietnam era only
  • February 1955 to July 1964 only
  • Vietnam era and Korean conflict
  • Korean conflict only
  • Korean conflict and World War II
  • World War II
  • World War I
  • Other service

Responses to period of service were edited by computer for consistency with age.

Historical comparability
Questions providing detailed data on veteran status have been asked since 1960. For 1980, the questions on veteran status and period of service are designed, for the first time, to include women as well as men. The 1970 counterpart item was asked only of men and identified two fewer periods of service.

Walkup
See "Stories in Structure".

Water Cost
See "Energy Costs, Monthly Residential".

Water Heating Fuel
See "Fuel".

Water, Source Of
Source of the water used by the occupants or intended occupants of the housing unit, ascertained for occupied and vacant housing units. This item was asked on a sample basis.

Public system or private company
A common source supplying running water to six or more housing units. The water may be supplied by a city or county water department, a water district, a private water company, etc., or it may be obtained from a well which supplies six or more housing units.

Individual well
Water obtained from a well on the property of the unit being numerated or on a neighboring property providing water to five or fewer housing units. The well water may be hand drawn, wind drawn, or engine drawn; piped or not piped; stored in tanks; or used directly from the well.

Drilled
A well generally made with a mechanical drilling rig and less than 1 1/2 feet in diameter. Drilled wells include artisian (natural spring) wells.

Dug well
A well generally hand dug and wider than 1 1/2 feet in diameter.

Some other source
Water obtained from springs, creeks, rivers, ponds, lakes, cisterns, or other sources not listed, but not from a public system, private company, or well.

Historical comparability
Similar data were collected in 1960 and 1970; in 1960, however, data were collected only outside cities with 50,000 or more persons. The distinction between drilled wells and dug wells is new for 1980.

Weeks of Unemployment In 1979
The number of weeks during 1979 in which a person did not work but was looking for work or was on layoff from a job, tabulated for persons who did not work in 1979 or worked less than 52 weeks. Excluded from weeks of unemployment is any week in which the person worked (even for 1 hour), any week for which the person received wages or salary, or any week in which the person was on active duty in the Armed Forces, on paid vacation, or on paid leave. The question on weeks of unemployment did not ask whether the person was available to accept a job. (See the definition of unemployed under Labor Force Status. This item was collected on a sample basis.

Persons 16 years old and over with unemployment in 1979 were classified as follows: unemployed 1 to 4 weeks, 5 to 14 weeks, 15 to 26 weeks, and 27 weeks or more. Census basic records and public-use microdata record the actual number of weeks unemployed.

Historical comparability
New item for 1980. Data on weeks of unemployment were last collected in the 1950 census.

See also: "Labor Force Status In 1979".

Weeks Worked In 1979
The number of weeks during 1979 in which a person did any work for pay or profit (including paid vacation and paid sick leave) or worked without pay on a family farm or in a family business. Weeks of active service in the Armed Forces are also included. These data are tabulated for all persons 16 years old and over who worked in 1979, regardless of current labor force status. This item was collected on a sample basis.

Census basic records and public-use microdata record the actual number of weeks worked, 1 to 52. Categories available in detailed tabulations include: 13 weeks or less, 14 to 26 weeks, 27 to 39 weeks, 40 to 47 weeks, 48 to 49 weeks, and 50 to 52 weeks. Statistics on weeks worked in 1979 can be used to put 1979 earnings in the appropriate perspective.

Limitations
It is probable that the number of persons who worked in 1979 and the number of weeks they worked are understated since there is some tendency for respondents to forget intermittent or short periods of employment or to exclude weeks worked without pay. An evaluation study of 1970 census data on weeks worked last year found moderate consistency in the classification of persons who worked 50 to 52 weeks in 1969, but a high degree of variability for other weeks-worked categories.

Historical comparability
Data on weeks worked collected in the 1980 census are comparable to data from the 1960 and 1970 censuses, but may not be entirely comparable with data from the 1940 and 1950 censuses because of a different structure to the question. In 1970, data on weeks worked were collected in intervals.

See also: "Hours Worked Per Week In 1979;" "Labor Force Status In 1979;" "Weeks Unemployed In 1979".

See "Water, Source Of".

White Population
See "Race".

Work Disability
See "Disability".

Year Last Worked
The most recent year in which a person did any work for pay or profit, or worked without pay on a family farm or in a family business, or was on active duty in the Armed Forces. This item is tabulated for persons 16 years old and over who were not at work during the reference week. It was asked on a sample basis.

The data from this question are used to define "experienced unemployed" (See Labor Force Status), a concept which excluded unemployed persons who "never worked." In addition to persons who marked "never worked," persons who reported that they last worked when they were 14 years old or younger were assigned to the "never worked" category. Persons who last worked before 1975 were not asked to report the industry, occupation and class of worker of their last job.

Historical comparability
A comparable question was asked in the 1970 census.

See also: "Labor Force Status In 1979".

Year Moved Into Unit
The year of the householder's latest move into the housing unit, ascertained for occupied units. Respondents who had moved back into a unit they previously occupied were asked the year of the most recent move, as were those who moved from one apartment to another in the same building. This item also includes those who, living in a mobile home, moved from one location to another in the same mobile park. The intent of this question is to establish the length of occupancy by the present householder.

The year that the householder moved in is not necessarily the same year other members of the household moved, although in the great majority of cases an entire household moves at the same time. Respondents who indicated that they "always lived here" are assigned to the category corresponding to their year of birth. This item was asked on a sample basis.

Limitations
An evaluation study after the 1970 census found that the census figures for the year the household head moved into the unit substantially overstated the category "always lived here."

Historical comparability
In 1960 and 1970, ear Moved into Unit was asked of every person and included in population reports. Year Moved into Unit in housing tabulations referred to the year the head moved in. The 1970 questionnaire indicated seven time spans: 1949 or earlier, 1950 to 1959, 1960 to 1964, 1965 or 1966, 1967, 1966, and 1969 or 1970.

See also: "Residence In 1975".

Year-Round Housing Units
All occupied units plus vacant units intended for year-round use. Almost all data on housing characteristics are limited to year-round housing units. Vacant units held for seasonal use or migratory labor are excluded because it is difficult to obtain reliable information for them. Counts of the total housing inventory include both year-round and seasonal units.

See also: "Vacancy Status".

Year Structure Built
The year the original construction of the building was Completed (not the date of any of any later remodeling, addition, or conversion). This item was ascertained for occupied and vacant housing units. For housing units under construction which met the housing unit definition, i.e., all exterior windows, doors, and final usable floors in place, the category "1979 or March 1980" is used. For mobile homes, trailers, and houseboats, the manufacturer's model year is assumed to be the year built. For railroad cars, tents, caves, etc., the date "1939 or earlier" is used. The figures show the number of units in structures built during the specified periods and still in existence at the time of the census. This item was asked on a sample basis.

Limitations
Year-built data are particularly susceptible to response errors and nonreporting since respondents must rely on their memory or estimates of persons, who have lived in the neighborhood a long time, etc. A 1970 census evaluation study found greater inconsistencies between the census and reinterviews among earlier year-built categories than among categories for more recent periods.

Historical comparability
Similar data have been collected since 1940. The categories in 1970 were: 1939 or earlier, 1940 to 1949, 1950 to 1959, 1960 to 1964, 1965 to 1968, and 1969 to 1970.

Questionnaire Facsimile
For more information, please refer to:

Questionnaire Facsimile Codebook.pdf



Appendix A.
For more information, please refer to: Appendix A. Codebook 1980 SF3-7.pdf



Appendix B.
Appendix B1.
For more information, please refer to: Appendix B1 Codebook 1980 SF3-8.pdf

Appendix B2.
For more information, please refer to: Appendix B2 Codebook 1980 SF3-9.pdf

Appendix B3
Code List for Ancestry Entries
Ancestry refers to respondents' written entries on the census questionnaire. Some entries may appear to be indicative of race, country of origin, ethnicity, etc., but are not usable as such. Other entries (such as Eurasian) may be considered to be indicative of multiple entries, but are treated as single ancestry categories for census purposes.

The ancestry categories are not edited to be consistent with other responses for a person, and usage for other than ancestry tabulations may yield inconsistent or erroneous results.

For tallying, the following priority rules were established for identifying a person as being of single ancestry multiple ancestries, as having ancestry classified as not specified, or as having ancestry not reported.

Each person is assigned a 6-digit code. The first 3-digits comprise the primary ancestry code and the last 3 digits the secondary ancestry code.

1. A person is of single ancestry.

a. If the primary code is 0 to 899, 903 to 905, or 908 to 919 and the secondary code is 900 to 902, 906, 907 or 937-999. The single ancestry is that specified in the primary code.

b. If both the primary and secondary codes are 0 to 899, 903 to 905, or 908 to 919 and the primary and secondary codes are equal or are entries within a grouping defined as a common ancestry (see code ranges for common ancestry). (However, tally specifications may dictate variations in the common ancestry groupings.)

2. A person is of multiple ancestries.

a. If the primary code is 920 to 936. (Secondary code is irrelevant.)

b. If both the primary and secondary codes are 0 to 899, 903 to 905 or 908 to 919 and the primary and secondary codes are not entries within a grouping defined as a common ancestry.

3. A person is classified as having ancestry not specified, if the primary code is 900 to 902, 906, 907 or 937 to 998. (Secondary code is Irrelevant.)

4. A person is classified as not reported, if the primary code is 999 (Secondary code is irrelevant.)

Tabulations of ancestry may necessitate the counting of an individual more than once. For example, in a particular tabulation the category of persons of "English ancestry" could include those persons of mixed ancestry with English identified as one of the multiple origins as well as those who specify English as their only ancestry. Persons of multiple ancestries may also be tabulated for each of the other ancestry groups depending on the tally specifications. Following is a list of the ancestry categories and codes:

For more information, please refer to: Code List fo Ancestry Entries Codebook 1980 SF3-10.pdf

Appendix B4
Code List For Type Of Group Quarters
Note: The population is divided into "noninstitutional" and "institutional" persons. To determine the appropriate classification, the type of living quarters (i.e., housing unit, institutional group quarters, or noninstitutional group quarters) and sometimes relationship (inmate or noninmate) must be considered. All persons in housing units, all persons in noninstitutional group quarters and persons who are not inmates but who live in institutional group quarters are classified as "noninstitutional." Only those persons in institutional group quarters with a relationship of "inmate" are classified as "institutional."

For more information, please refer to: Code List for Type of Group Quraters Codebook 1980 SF3-11.pdf

Appendix B5
Industry Classification Codes
(Numbers in parentheses are the 1972 SIC code equivalents: see Executive Office of the President, Office of Management and Budget, Standard Industrial Classification Manual, 1972 and the 1977 Supplement. "Pt" means part; "n.e.c. " means not elsewhere classified.)

For more information, please refer to: Appendix B5. Industry Classification Codes Codebook 1980 SF3-12.pdf

Appendix B6
(Numbers in parentheses are the 1980 SOC code equivalent; see U.S. Department of Commerce, Office of Federal Statistical Policy and Standards. Standard Occupational Classification Manual, 1980. "Pt" means part; "n.e.c." means not elsewhere classified.)

For more information, please refer to: Appendix B6. Occupational Classification Codes for Detailed Occupational Categories.pdf

Appendix B7.
1980 Census Labor Force Status Categories
Description Code
In labor force:  
  Civilian labor force:  
    Employed:  
    At work 1
    With a job, but not at work 2
    Unemployed 3
  Armed Forces:  
    At work 4
    With a job, but not at work 5
Not in labor force 6

  • Note 1: For tabulations of Place-of-work item, the concept "workers" is defined as code 1 and code 4 above.
  • Note 2: For the derived measure, "Nonworkers per 100 workers," the denominator "worker" is defined as codes 1, 2, 3, 4, and 5. The numerator is defined as code 6 plus all persons under 16 years of age.
  • Note 3: The concept "Workers in 1979" does not refer to the above codes.