Codes and Frequencies
USBORN indicates whether the respondent was born in the United States. To collect this information, interviewers asked, "Where were you born?" Responses were recoded in the original NHIS public use files into the categories included in this variable.
Take note: Changes in the definition of U.S. born
In 1997-2001, the available codes distinguished between born in a U.S. state or D.C. or born outside of the U.S., where "outside of the U.S." included being born in a U.S. territory. In 2002, an additional category, "born in a U.S. territory" was introduced as distinct from born outside of the U.S. In 2019, the available codes changed so that born in the 50 states or D.C. was combined into a single category with born in a U.S. territory, distinguished from born outside of the U.S. or U.S. territory.
According to the 2020 Survey Description, for some variables, including USBORN, the 2020 responses of sample adults that were part of the 2020 longitudinal sample were overwritten with their 2019 responses "to mitigate disclosure risks associated with differences in response from repeated measures among the same Sample Adults" (33). The sample adults' actual 2020 responses can be accessed through a Research Data Center (RDC). For more information on the 2020 longitudinal sample, please see SALNGPRTFLG.
- REGIONBR provides additional detail on the place of birth of respondents born outside the United States. In REGIONBR, respondents' reported countries of birth were recoded in the original NHIS public use files into 12 broad regional categories.
- CITIZEN provides information on whether the person is a citizen of the U.S.
Changes in the categories of USBORN and the meaning of "born in the U.S." affect comparability over time.
Persons born in any of the 50 states or in the District of Columbia are consistently identified (code 20) in USBORN. For 1997-2001, all persons born outside these areas are grouped together. Between 2002-2018, the data distinguish between persons born outside of a U.S. state or D.C., but within a U.S. territory (including Puerto Rico, Guam, and other outlying territories of the United States) and those born elsewhere outside the United States. Beginning in 2019, code 20 ("born in U.S.") combines those born in a U.S. state or D.C. and those born in a U.S. territory into a single category. Because of this change in the meaning of "born in the U.S.," users can create comparable categories between the 1997-2001 and 2002-2018 periods, and between the 2002-2018 and 2019-forward periods, but not between the 1997-2001 and 2019-forward periods.
The introduction of a substantially revised questionnaire in 2019 may also affect comparability with earlier years. The NHIS questionnaire was substantially redesigned in 2019 to introduce a different data collection structure and new content. For more information on changes in terminology, universes, and data collection methods beginning in 2019, please see the user note.
- 1997-2018: All persons.
- 2019-2021: Sample children age 0-17 and sample adults age 18+.
- 1997-2018 : PERWEIGHT
- 2019-2021 : SAMPWEIGHT