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National Health Interview Survey

Description: 

The National Health Interview Survey (NHIS) monitors the health of the United States population through the collection and analysis of data on a broad range of health topics. The survey covers the civilian noninstitutionalized population residing in the United States at the time of the interview. Black, Hispanic, and Asian persons are oversampled. The questionnaire has Core questions and Supplements. Core questions remain largely unchanged from year to year and allow for trends analysis and for data from more than one year to be pooled to increase sample size for analytic purposes. The Core contains four major components: Household, Family, Sample Adult, and Sample Child. The Household component collects limited demographic information on all of the individuals living in a particular house. The Family component verifies and collects additional demographic information on each member from each family in the house and collects data on topics including health status and limitations, injuries, healthcare access and utilization, health insurance, and income and assets. The Supplements are used to respond to new public health data needs as they arise. The questionnaires are sometimes fielded only once or are repeated as needed. These questionnaires may be used to provide additional detail on a subject already covered in the Core or on a different topic not covered in other parts of the NHIS.

Data Years Available: 
1957-present
Periodicity: 
Annual
Mode of Collection: 
Personal interviews in households using computer-assisted personal interviewing (CAPI).
Selected Content: 
Information is obtained on demographic characteristics, illnesses, injuries, impairments, chronic conditions, utilization of health resources, health insurance, and other health topics (e.g., chronic health conditions and limitations in activity, health behaviors, health care access, health care provider contacts, immunizations and AIDS knowledge and attitudes). The supplements cover topics such as Cancer Screening, Complementary and Alternative Medicine, Children’s Mental Health, and Healthcare Utilization.
Population Covered: 
The U.S. civilian noninstitutionalized population.
Methodology: 
NHIS is a cross-sectional household interview survey. Sampling and interviewing are continuous throughout the year. The sampling plan follows a multistage area probability design that permits the representative sampling of households. The sampling plan is redesigned after every decennial census; The current plan was implemented in 2006. It has many similarities to the previous sampling plan, which was in place from 1995 to 2005. The first stage of the current plan consists of a sample of 428 primary sampling units (PSU's) drawn from approximately 1,900 geographically defined PSU's that cover the 50 States and the District of Columbia. A PSU consists of a county, a small group of counties, or a metropolitan statistical area. The total NHIS sample is subdivided into four separate panels, or subdesigns, such that each panel is a representative sample of the U.S. population. The households selected for interview each week are a probability sample representative of the target population.
Response Rates and Sample Size: 
In 2007, the sample numbered 75,764 with 23,393 persons participating in the Sample Adult and 9,417 in the Sample Child questionnaires. The total household response rate was 87%. The final response rate for the Sample Adult file was 68% and for the Sample Child file was 77%.
Interpretation Issues: 
In 1997, the NHIS questionnaire underwent a major redesign. The redesign has resulted in comparability issues in trend data before and after the redesign.
References: 

National Center for Health Statistics. Health United States 2009: With Special Feature on Medical Technology. Hyattsville, Maryland. 2010; pp 465-466.