| **National Center    for     Health Statistics            Division of Data     Services            6525 Belcrest Road     Hyattsville, MD     20782-2003     (301)458-4636      **

 

**National Health Interview Survey    (NHIS)NCHS Home | NHIS Home | Description | 1997 NHIS | 1998 NHIS1999 NHIS | NHIS    on Disability | News Releases and    Fact SheetsData Highlights | Coming Events | Methods    | PublicationsMicro-data | Related    Links | Other Federal AgenciesSearch NCHS | Contact us**
**Sample Design**

The National Health Interview Survey is    a cross-sectional household interview survey. Sampling and interviewing are continuous    throughout each year. The sampling plan follows a multistage area probability design that    permits the representative sampling of households. The sampling plan was redesigned in    1995. Information about the sampling plan given here covers the design years     1995-2004. The first stage consists of a sample of 358 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 contiguous    counties, or a metropolitan statistical area. 

Within a PSU, two types of second-stage    units are used, area segments and permit area segments. Area segments are defined    geographically and contain an expected 8 or 12 addresses. Permit area segments cover    geographical areas containing housing units built after the 1990 census. The permit area    segments are defined using updated lists of building permits issued in the PSU since 1990    and contain an expected four addresses. Within each segment all occupied households at the    sample addresses are targeted for interview.

The NHIS sample design implemented with    the 1995 data collection year was a complete redesign from that used during 1985-94. A    feature added for the 1995 sample design is the oversampling of both Black persons and    Hispanic persons. Another feature added is that the NHIS sample is now drawn from each    State. Although the NHIS sample is too small to provide State-level data with acceptable    precision for each State, this design will facilitate the use of NHIS data with    State-level telephone health surveys. 

The total NHIS sample of PSU's is    subdivided into four separate panels or subdesigns, such that each panel is a    representative sample of the U.S. population. This design feature has a number of    advantages, including flexibility for the total sample size. The 1995 NHIS sample included    all four panels. In the first half of 1996, the NHIS fielded the traditional pencil and    paper NHIS questionnaire in 3 panels; in the second half of 1996 the NHIS fielded the    traditional pencil and paper NHIS in 2 panels; most of the residual 1996 NHIS sample was    used for the development of the revised NHIS questionnaire. 

The households selected for interview    each week in the NHIS are a probability sample representative of the target population.    With four sample panels, NHIS data are collected annually from approximately 43,000    households including about 106,000 persons. Survey participation is voluntary and the    confidentiality of responses is assured under Section 308(d) of the Public Health Service    Act. The annual response rate of NHIS is greater than 90 percent of the eligible    households in the sample.

 

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This page last reviewed July 25, 2000

**U.S.    DEPARTMENT OF HEALTH AND HUMAN SERVICES****Centers    for Disease Control and Prevention**    National Center for Health Statistics    Division of Data Services     Hyattsville, MD    20782-2003    (301) 458-4636
 

 

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