Data Dictionary: Census 1990
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Survey: Census 1990
Data Source: U.S. Census Bureau
Table: P30. Age, Language Spoken At Home, And Linguistic Isolation [52]
Universe: Persons 5 years and over
Table Details
P30. Age, Language Spoken At Home, And Linguistic Isolation
Universe: Persons 5 years and over
Variable Label
P030_001
P030_002
P030_003
P030_004
P030_005
P030_006
P030_007
P030_008
P030_009
P030_010
P030_011
P030_012
P030_013
P030_014
P030_015
P030_016
P030_017
P030_018
P030_019
P030_020
P030_021
P030_022
P030_023
P030_024
P030_025
P030_026
P030_027
P030_028
P030_029
P030_030
P030_031
P030_032
P030_033
P030_034
P030_035
P030_036
P030_037
P030_038
P030_039
P030_040
P030_041
P030_042
P030_043
P030_044
P030_045
P030_046
P030_047
P030_048
P030_049
P030_050
P030_051
P030_052
Relevant Documentation:
Excerpt from: Social Explorer, U.S. Census Bureau; Census of Population and Housing, 1990: Summary Tape File 3 on CD-ROM [machine-readable data files] / prepared by the Bureau of the Census. Washington: The Bureau [producer and distributor], 1991.
 
Age
The data on age were derived from answers to questionnaire item 5, which was asked of all persons. The age classification is based on the age of the person in complete years as of April 1, 1990. The age response in question 5a was used normally to represent a person's age. However, when the age response was unacceptable or unavailable, a person's age was derived from an acceptable year-of-birth response in question 5b.

Data on age are used to determine the applicability of other questions for a person and to classify other characteristics in census tabulations. Age data are needed to interpret most social and economic characteristics used to plan and examine many programs and policies. Therefore, age is tabulated by single years of age and by many different groupings, such as 5-year age groups.

Some tabulations are shown by the age of the householder. These data were derived from the age responses for each householder. (For more information on householder, see the discussion under "Household Type and Relationship.")

Median Age
This measure divides the age distribution into two equal parts: one-half of the cases falling below the median value and one-half above the value. Generally, median age is computed on the basis of more detailed age intervals than are shown in some census publications; 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. (For more information on medians, see the discussion under "Derived Measures.")

Limitation of the Data
Counts in 1970 and 1980 for persons 100 years old and over were substantially overstated. Improvements were made in the questionnaire design, in the allocation procedures, and to the respondent instruction guide to attempt to minimize this problem for the 1990 census.

Review of detailed 1990 census information indicated that respondents tended to provide their age as of the date of completion of the questionnaire, not their age as of April 1, 1990. In addition, there may have been a tendency for respondents to round their age up if they were close to having a birthday. It is likely that approximately 10 percent of persons in most age groups are actually 1 year younger. For most single years of age, the misstatements are largely offsetting. The problem is most pronounced at age 0 because persons lost to age 1 may not have been fully offset by the inclusion of babies born after April 1, 1990, and because there may have been more rounding up to age 1 to avoid reporting age as 0 years. (Age in complete months was not collected for infants under age 1.)

The reporting of age 1 year older than age on April 1, 1990, is likely to have been greater in areas where the census data were collected later in 1990. The magnitude of this problem was much less in the three previous censuses where age was typically derived from respondent data on year of birth and quarter of birth. (For more information on the design of the age question, see the section below that discusses "Comparability.")

Comparability
Age data have been collected in every census. For the first time since 1950, the 1990 data are not available by quarter year of age. This change was made so that coded information could be obtained for both age and year of birth. In each census since 1940, the age of a person was assigned when it was not reported. In censuses before 1940, with the exception of 1880, persons of unknown age were shown as a separate category. Since 1960, assignment of unknown age has been performed by a general procedure described as "imputation." The specific procedures for imputing age have been different in each census. (For more information on imputation, see Appendix C, Accuracy of the Data.)

Excerpt from: Social Explorer, U.S. Census Bureau; Census of Population and Housing, 1990: Summary Tape File 3 on CD-ROM [machine-readable data files] / prepared by the Bureau of the Census. Washington: The Bureau [producer and distributor], 1991.
 
Household Language
In households where one or more persons (age 5 years old or over) speak a language other than English, the household language assigned to all household members is the non-English language spoken by the first person with a non-English language in the following order:

householder, spouse, parent, sibling, child, grandchild, other relative, stepchild, unmarried partner, housemate or roommate, roomer, boarder, or foster child, or other nonrelative. Thus, persons who speak only English may have a non-English household language assigned to them in tabulations of persons by household language.

Figure 1. Four- and Twenty-Five-Group Classifications of 1990 Census Languages Spoken at Home with Illustrative Examples
Four-Group Classification Twenty-Five-Group Classification Examples
Spanish Other Indo-European Spanish Spanish, Ladino
  French French, Cajun,French Creole
  Italian  
  Portuguese  
  German  
  Yiddish  
  Other West Afrikaans, Dutch,
  Germanic Pennsylvania Dutch
  Scandanavian Danish, Norwegian, Swedish
  Polish  
  Russian  
  South Slavic Serbocroatian, Bulgarian, Macedonian, Slovene
  Other Slavic Czech, Slovak, Ukranian
  Greek  
  Indic Hindi, Bengali, Gujarathi, Punjabi, Romany, Sinhalese
  Other Indo European, Armenian, Gaelic,
  not elsewhere classified Lithuanian, Persian
Languages of Asia and the Pacific Chinese  
  Japanese  
  Mon-Khmer Cambodian
  Tagalog  
  Korean  
  Vietnamese  
  Other languages Chamorro, Dravidian
  (part) Languages, Hawaiian,
    Ilocano, Thai, Turkish
All other languages Arabic  
  Hungarian  
  Native North  
  American languages  
  Other languages Amharic, Syriac,
  (part) Finnish, Hebrew,
    Languages of
    Central and South
    America, Other
    Languages of Africa


Excerpt from: Social Explorer, U.S. Census Bureau; Census of Population and Housing, 1990: Summary Tape File 3 on CD-ROM [machine-readable data files] / prepared by the Bureau of the Census. Washington: The Bureau [producer and distributor], 1991.
 
Linguistic Isolation
A household in which no person age 14 years or over speaks only English and no person age 14 years or over who speaks a language other than English speaks English "Very well" is classified as "linguistically isolated." All the members of a linguistically isolated household are tabulated as linguistically isolated, including members under age 14 years who may speak only English.