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.")

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.

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.

The data on the Hispanic or Latino population were derived from answers to a question that was asked of all people. The terms "Spanish,""Hispanic origin," and "Latino" are used interchangeably. Some respondents identify with all three terms while others may identify with only one of these three specific terms. Hispanics or Latinos who identify with the terms "Spanish,"" Hispanic," or "Latino" are those who classify themselves in one of the specific Spanish, Hispanic, or Latino categories listed on the questionnaire ("Mexican,""Puerto Rican," or "Cuban") as well as those who indicate that they are "other Spanish/Hispanic/Latino." People who do not identify with one of the specific origins listed on the questionnaire but indicate that they are "other Spanish, Hispanic, or Latino" are those whose origins are from Spain, the Spanish-speaking countries of Central or South America, the Dominican Republic, or people identifying themselves generally as Spanish, Spanish-American, Hispanic, Hispano, Latino, and so on. All write-in responses to the "other Spanish/Hispanic/Latino" category were coded.

Origin can be viewed as the heritage, nationality group, lineage, or country of birth of the person or the persons parents or ancestors before their arrival in the United States. People who identify their origin as Spanish, Hispanic, or Latino may be of any race. Some tabulations are shown by the origin of the householder. In all cases where the origin of households, families, or occupied housing units is classified as Spanish, Hispanic, or Latino, the origin of the householder is used. (See the discussion of householder under "Household Type and Relationship.")

If an individual could not provide a Hispanic origin response, their origin was assigned using specific rules of precedence of household relationship. For example, if origin was missing for a natural-born daughter in the household, then either the origin of the householder, another naturalborn child, or spouse of the householder was assigned. If Hispanic origin was not reported for anyone in the household, the Hispanic origin of a householder in a previously processed household with the same race was assigned. This procedure is a variation of the general imputation procedures described in "Accuracy of the Data" and is similar to those used in 1990, except for Census 2000 race and Spanish surnames were used to assist in assigning an origin (see the "Comparability" section below also).