Data Dictionary: Census 2000
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Survey: Census 2000
Data Source: U.S. Census Bureau
Universe: People who are Two or more races
Variable Details
PCT12G. Sex By Age (Two Or More Races)
Universe: People who are Two or more races
Aggregation method:
Addition
Relevant Documentation:
Excerpt from: Social Explorer, U.S. Census Bureau; 2000 Census of Population and Housing, Summary File 1: Technical Documentation, 2001.
 
Sex
The data on sex were derived from answers to a question that was asked of all people. Individuals were asked to mark either "male" or "female" to indicate their sex. For most cases in which sex was not reported, it was determined by the appropriate entry from the persons given (i.e., first) name and household relationship. Otherwise, sex was imputed according to the relationship to the householder and the age of the person. (For more information on imputation, see "Accuracy of the Data.")

Sex ratio
A measure derived by dividing the total number of males by the total number of females and multiplying by 100.

Comparability
A question on the sex of individuals has been asked of the total population in every census.
For more information on sex, please telephone 301-457-2378.

Excerpt from: Social Explorer, U.S. Census Bureau; 2000 Census of Population and Housing, Summary File 1: Technical Documentation, 2001.
 
Age
The data on age were derived from answers to a question that was asked of all people. The age classification is based on the age of the person in complete years as of April 1, 2000. The age of the person was usually derived from their date of birth information. Their reported age was used only when date of birth information was unavailable.

Data on age are used to determine the applicability of some of the sample 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.

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. Median age is computed on the basis of a single year of age distribution.

Limitation of the data
The most general limitation for many decades has been the tendency of people to overreport ages or years of birth that end in zero or five. This phenomenon is called "age heaping." In addition, the counts in the 1970 and 1980 censuses for people 100 years old and over were substantially overstated. So also were the counts of people aged 69 in 1970 and aged 79 in 1980. Improvements have been made since then in the questionnaire design, and in the allocation procedures which have further minimized these problems. The count of people aged 89 in the 1990 census was not overstated.

Review of detailed 1990 census information indicated that respondents tended to provide their age as of the date they completed the questionnaire, not their age as of April 1, 1990. One reason this happened was that respondents were not specifically instructed to provide their age as of April 1, 1990. Another reason was that data collection efforts continued well past the census date. 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 people in most age groups were actually one year younger. For most single years of age, the misstatements were largely offsetting. The problem is most pronounced at age zero because people lost to age one probably were not fully offset by the inclusion of babies born after April 1, 1990. Also, there may have been more rounding up to age one to avoid reporting age as zero years. (Age in complete months was not collected for infants under age one.)

The reporting of age one year older than true age on April 1, 1990, is likely to have been greater in areas where the census data were collected later in calendar year 1990. The magnitude of this problem was much less in the 1960, 1970, and 1980 censuses where age was typically derived from respondent data on year of birth and quarter of birth.

These shortcomings were minimized in Census 2000 because age was usually calculated from exact date of birth and because respondents were specifically asked to provide their age as of April 1, 2000. (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 were 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 2000, each individual has both an age and an exact date 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, people 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 "Accuracy of the Data.")
For more information on age, please telephone 301-457-2428.

Excerpt from: Social Explorer, U.S. Census Bureau; 2000 Census of Population and Housing, Summary File 1: Technical Documentation, 2001.
 
Two or more races
People may have chosen to provide two or more races either by checking two or more race response check boxes, by providing multiple write-in responses, or by some combination of check boxes and write-in responses. The race response categories shown on the questionnaire are collapsed into the five minimum race groups identified by the OMB, and the Census Bureau "Some other race" category. For data product purposes, "Two or more races" refers to combinations of two or more of the following race categories:
  1. White
  2. Black or African American
  3. American Indian and Alaska Native
  4. Asian
  5. Native Hawaiian and Other Pacific Islander
  6. Some other race
There are 57 possible combinations (see Figure B-1) involving the race categories shown above. Thus, according to this approach, a response of "White" and "Asian" was tallied as two or more races, while a response of "Japanese" and "Chinese" was not because "Japanese" and "Chinese" are both Asian responses. Tabulations of responses involving reporting of two or more races within the American Indian and Alaska Native, Asian, or Native Hawaiian and Other Pacific Islander categories are available in other data products.

Given the many possible ways of displaying data on two or more races, data products will provide varying levels of detail. The most common presentation shows a single line indicating "Two or more races." Some data products provide totals of all 57 possible combinations of two or more races, as well as subtotals of people reporting a specific number of races, such as people reporting two races, people reporting three races, and so on.

In other presentations on race, data are shown for the total number of people who reported one of the six categories alone or in combination with one or more other race categories. For example, the category "Asian alone or in combination with one or more other races" includes people who reported Asian alone and people who reported Asian in combination with White, Black or African American, Native Hawaiian and Other Pacific Islander, and Some other race. This number, therefore, represents the maximum number of people who reported as Asian in the question on race. When this data presentation is used, the individual race categories will add to more than the total population because people may be included in more than one category.