When information is missing or inconsistent, the Census Bureau uses a method called imputation to assign values. Imputation relies on the statistical principle of "homogeneity," or the tendency of households within a small geographic area to be similar in most characteristics. For example, the value of "rented" is likely to be imputed for a housing unit not reporting on owner/renter status in a neighborhood with multiunits or apartments where other respondents reported "rented" on the census questionnaire. In past censuses, when the occupancy status or the number of residents was not known for a housing unit, this information was imputed.

The data on citizenship were derived from answers to long-form questionnaire Item 13, which was asked of a sample of the population. On the stateside questionnaire, respondents were asked to select one of five categories: (1) born in the United States, (2) born in Puerto Rico or a U.S. Island Area (such as Guam), (3) born abroad of American parent(s), (4) naturalized citizen, (5) not a citizen. On the Puerto Rico questionnaire, respondents were asked to select one of five categories: (1) born in Puerto Rico, (2) born in a U.S. state, District of Columbia, Guam, the U.S. Virgin Islands, or the Northern Mariana Islands, (3) born abroad of American parent or parent(s), (4) U.S. citizen by naturalization, (5) not a citizen of the United States. People not reporting citizenship were assigned citizenship based on a set of criteria including the citizenship status of other household members and place of birth. (See "Place of Birth.")