clude people found at soup kitchens or street locations frequented by the homeless and a few other transient situations. Table 2-1 lists the types of residences included in the 2006 ACS.

Residence Rules

The ACS instructs the respondent for a household to provide data on all people who, at the time of filling out the questionnaire, are living or staying at the household address for more than 2 months (including usual residents who are away for less than 2 months). In contrast, the long-form sample asked household respondents to report all people who usually lived at the address as of Census Day, April 1, meaning they lived or stayed there most of the time. People whom the ACS samples in group quarters beginning in 2006 are counted at the group quarters location, in effect applying a de facto residence rule regardless of how long an individual has lived or expects to live in the group quarters. The long-form sample also in effect generally applied a de facto residence rule for group quarters residents, although residents of some types of group quarters were allowed the option of indicating another usual place of residence. (An unduplication process was used to determine the correct enumeration for people listed at the group quarters and the other residence; such a process would not be possible for the ACS because it is not embedded in a census.)

For many people, their ACS residence will be the same as their long-form-sample residence. However, some people may report a different residence: for example, people who live in a house or apartment in New York most of the year but reside in Florida in December through March should report Florida as their address if sampled for the ACS in Florida in the winter, whereas their Census Day address is in New York.

Content and Reference Periods

The 2005 ACS includes about 55 questions for every person and 30 questions for every housing unit in the sample—approximately the same content as in the 2000 census long-form sample. There are some differences:

  • The ACS mail questionnaire uses a matrix layout for questions on sex, age, race, ethnicity, and household relationship, compared with a person-by-person format in the long-form questionnaire.

  • The ACS mail questionnaire provides room to respond for 5 household members compared with 6 on the long-form questionnaire (telephone follow-up is used to obtain information on additional household members).

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