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National Healthcare Disparities Report, 2005

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National Health and Nutrition Examination Survey (NHANES)


U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS).

Mode of Administration

In-person interview in the household and in a private setting in the mobile examination center. Standardized physical examinations and medical tests in mobile examination centers.

Survey Sample Design

The NHANES uses a stratified multistage probability sample, nationally representative of the U.S. civilian noninstitutionalized population. The NHANES III survey is designed to be nationally representative for either Phase I or II of data collection (1988-1994). The NHANES 1999-2004 survey is designed to give an annual sample that is nationally representative, and approximately 5,000 people are examined at 15 locations each year, with over sampling of African Americans, Mexican Americans, adolescents, older persons and low income Whites.

The current NHANES are released in two year datasets, and NHANES 2001-2002 is the most recent data release. The sample size is smaller than NHANES III, and the number of geographic units in the sample is more limited. The sample design, weighting, and variance estimation methodology also differ from NHANES III.

Response Rates

In NHANES III (1984-1994): Household interview response rate is 86 percent and the medical examination response rate is 78 percent.

In NHANES 1999-2000: Household interview response rate is 82 percent and the medical examination response rate is 76 percent.

In NHANES 2001-2002: Household interview response rate is 84 percent and the medical examination response rate is 80 percent.

Primary Survey Content

Chronic disease prevalence and conditions (including undiagnosed conditions), risk factors, diet and nutritional status, immunization status, infectious disease prevalence, health insurance, and measures of environmental exposures. Other topics addressed include hearing, vision, mental health, anemia, diabetes, cardiovascular disease, osteoporosis, obesity, oral health, mental health, and physical fitness.

Population Targeted

For NHANES III, the civilian noninstitutionalized population residing in the United States aged two months and over. Beginning in 1999, people of all ages are included.

Demographic Data

Gender, age, education, race/ethnicity, place of birth, income, occupation, and industry.

Years Collected

From 1960 to 1994, a total of seven national examination surveys have been conducted. Beginning in 1999, the survey has been conducted continuously.


Fielded periodically (1960-94); continuously beginning in 1999, with data releases occurring in two year increments.

Geographic Estimates

National; four U.S. Census Bureau regions (NHANES III).

Contact Information

Agency homepage:

Data system homepage:


National Center for Health Statistics. Plan and operation of the third National Health and Nutrition Examination Survey, 1988-94. National Center for Health Statistics (NCHS). Vital and Health Statistics1(32), 1994.

NHANES 1999-2000 Addendum to the NHANES III Analytic Guidelines (updated August 2002) and NHANES Analytic Guidelines (June 2004 Version), both available at



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