Codes and Frequencies
Comparability
Universe and survey redesign changes introduced in 2019 affect the comparability between 2019-forward and 2018 and earlier samples. Beginning in 2019, marital status information was only collected for sample adults aged 18 and older and marital status for younger persons is unknown; beginning in 2019, sample children aged 18 and younger were all coded as "not in universe." Prior to 2019, marital status information was collected for all persons age 15 and older and children under 15 were coded as "never married."
Questionnaire design changes introduced in 2019 limit 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.
Universe
- 1997-2018: All persons.
- 2019-2022: Sample adults age 18+.
Availability
- 1997-2022
Weights
- 1997-2018 : PERWEIGHT
- 2019-2022 : SAMPWEIGHT