Division of Health Interview Statistics
National Center for Health Statistics
Hyattsville, MD

Centers for Disease Control and Prevention
U.S. Department of Health and Human Services
February 2000

The National Health Interview Survey (NHIS) is a multi-purpose health survey conducted by the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention (CDC), and is the principal source of information on the health of the civilian, noninstitutionalized, household population of the United States. The NHIS has been conducted continuously since its beginning in 1957. Data are released on an annual basis.

The NHIS Core questionnaire items were revised every 10-15 years, with the last major revision occurring in 1982. The NHIS that was fielded from 1982-1996 consisted of two parts: (1) a set of basic health and demographic items (known as the Core questionnaire), and (2) one or more sets of questions (called Supplements) on current health topics. Despite periodic revisions to the Core questionnaire, Supplements played an increasingly important role in the survey as a means of enhancing topic coverage in the Core. Eventually, certain Supplements, such as "Family Resources" and "Childhood Immunization,? were incorporated in the NHIS Core on an annual basis.

However, the unintended result was an increasingly unwieldy survey instrument and longer interviewing sessions: recent questionnaires (Core and Supplements combined) ran almost 300 pages, while interviews averaged two hours. This imposed an unacceptable burden on NCHS staff, U.S. Bureau of the Census interviewers, the data collection budget, and, most importantly, on the NHIS respondents. Furthermore, the excessive length of NHIS interviews contributed to declines in both response rate and data quality. For all of these reasons, NCHS initiated a redesign of the NHIS questionnaire that was implemented in 1997.