2019–present. The National Health Interview Survey (NHIS) is a nationally representative household health survey of the U.S. civilian noninstitutionalized population. The NHIS data are used to monitor trends in illness and disability, track progress toward achieving national health objectives, for epidemiologic and policy analysis of various health problems, determining barriers to accessing and using appropriate health care, and evaluating Federal health programs. NHIS is conducted continuously throughout the year by the National Center for Health Statistics (NCHS). Public-use data files on adults and children with corresponding imputed income data files, and survey paradata are released annually. The NHIS data website (
https://www.cdc.gov/nchs/nhis/data-questionnaires-documentation.htm) features the most up-to-date public-use data files and documentation for downloading including questionnaire, codebooks, CSV and ASCII data files, programs and sample code, and in-depth survey description. Most of the NHIS data are included in the public use files. NHIS is protected by Federal confidentiality laws that state the data collected by NCHS may be used only for statistical reporting and analysis. Some NHIS variables have been suppressed or edited in the public use files to protect confidentiality. Analysts interested in using data that has been suppressed or edited may apply for access through the NCHS Research Data Center at
https://www.cdc.gov/rdc/. In 2019, NHIS launched a redesigned content and structure that differs from its previous questionnaire designs. NHIS has been conducted continuously since 1957.
