The National Health Interview Survey (NHIS) is an annual, cross-sectional survey intended to provide nationally representative estimates on a wide range of health status and utilization measures among the nonmilitary, noninstitutionalized population of the United States. Each annual data set can be used to examine the disease burden and access to care that individuals and families are currently experiencing in the United States. NHIS is designed by the CDC's National Center for Health Statistics (NCHS) – the government agency tasked to monitor the population's health status and behavior – and administered by the U.S. Census Bureau. NHIS has been administered since 1957, although the core content and questionnaires undergo major revisions every 10–15 years. NHIS allows both governmental and outside researchers to obtain estimates on a variety of health-related topics among either the entire nation or specific demographic groups of the population. Also, since the survey design is cross-sectional rather than longitudinal, health information can be trended for demographic groups and the country as a whole, but not for individuals or families. From Wikipedia
