National Health Interview Survey, 2008 (ICPSR 27341)

Published: Aug 26, 2010

Principal Investigator(s):
United States Department of Health and Human Services. Centers for Disease Control and Prevention. National Center for Health Statistics


Version V3

The purpose of the National Health Interview Survey (NHIS) is to obtain information about the amount and distribution of illness, its effects in terms of disability and chronic impairments, and the kinds of health services people receive. Implementation of a redesigned NHIS, consisting of a basic module, a periodic module, and a topical module, began in 1997 (see NATIONAL HEALTH INTERVIEW SURVEY, 1997 [ICPSR 2954]). The 2008 NHIS contains the Household, Family, Person, Sample Adult, and Sample Child files from the basic module. Each record in Part 1, Household Level, contains data on type of living quarters, number of families in the household responding and not responding, and the month and year of the interview for each sampling unit. Part 2, Family Level, is made up of reconstructed variables from the person-level data of the basic module and includes information on sex, age, race, marital status, Hispanic origin, education, veteran status, family income, family size, major activities, health status, activity limits, and employment status, along with industry and occupation. As part of the basic module, Part 3, Person Level, provides information on all family members with respect to health status, limitation of daily activities, cognitive impairment, and health conditions. Also included are data on years at current residence, region variables, height, weight, bed days, doctor visits, hospital stays, and health care access and utilization. A randomly-selected adult in each family was interviewed for Part 4, Sample Adult, regarding respiratory conditions, renal conditions, AIDS, joint symptoms, health status, limitation of daily activities, and behaviors such as smoking, alcohol consumption, and physical activity. Additionally, questions regarding oral health, asthma, balance, cancer screening, heart disease, HPV, immunization, and vision were fielded. Part 5, Sample Child, provides information from an adult in the household on medical conditions of one child in the household, such as respiratory problems, seizures, allergies, and use of special equipment like hearing aids, braces, or wheelchairs. Also included are variables regarding child behavior, Attention Deficit Hyperactivity Disorder (ADHD), oral health, asthma, indoor tanning, HPV, immunization, mental health, and vision. Part 6, Injury/Poison Episode, is an episode-based file that contains information about the external cause and nature of the injury or poisoning episode and what the person was doing at the time of the injury or poisoning episode, in addition to the date and place of occurrence. Part 7, Injury/Poison Episode Verbatim, contains edited narrative text descriptions of the injury or poisoning, provided by the respondent. Part 8, Paradata, does not contain health related information, but rather data which are related to the interview process, including measures of time, contact-ability, and cooperation.

United States Department of Health and Human Services. Centers for Disease Control and Prevention. National Center for Health Statistics. National Health Interview Survey, 2008. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2010-08-26.

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In preparing the data files for this collection, the National Center for Health Statistics (NCHS) removed direct identifiers and characteristics that might lead to identification of data subjects. As an additional precaution, NCHS requires, under Section 308(d) of the Public Health Service Act (42 U.S.C. 242m), that data collected by NCHS not be used for any purpose other than statistical analysis and reporting. NCHS further requires that analysts not use the data to learn the identity of any persons or establishments and that the director of NCHS be notified if any identities are inadvertently discovered. ICPSR member institutions and other users ordering data from ICPSR are expected to adhere to these restrictions.



Beginning in 2005, the NHIS no longer allows an emancipated minor (someone between the ages of 14 and 17 living on their own without supervision of an adult family member or legal guardian) to be an eligible respondent or a sample adult or sample child. An emancipated minor is not eligible to be the respondent for the Sample Child questionnaire even if they are the parent of the sample child.

Imputed income files for 2008 are now available through the NCHS Web site.

Questionnaires have been provided in both English and Spanish.

To learn more about the National Health Interview Survey, visit the Centers for Disease Control and Prevention (CDC) Web site. At that site you can join the HISUSERS e-mail list by providing your name and e-mail address, selecting the item, "National Health Interview Survey (NHIS) researchers", and clicking on "subscribe".

Analysts should be aware that 263 persons who were active duty members of the Armed Forces at time of interview are on the Person-Level file and will appear in the unweighted frequencies, despite the fact that NHIS covers only the civilian noninstitutionalized household population. These active duty members of the Armed Forces are included in that file because at least one other family member is a civilian eligible for the survey. The value of the final annual person weight (WTFA) for these military persons is zero, so they will not be counted when making national (i.e., weighted) estimates.

The User Guide contains information regarding the merging of files and the use of weight variables, along with information regarding changes to the 2008 NHIS.

The NHIS uses a stratified multistage probability design. Oversampling of the Black and Hispanic populations has been retained in 2008 to allow for more precise estimation of health characteristics in these growing minority populations. The new sample design also oversamples the Asian population.

Civilian, noninstitutionalized population of the 50 states and the District of Columbia.

clinical data

survey data



2010-08-26 The Sample Adult Level (Part 0004) data files have been updated.

2010-08-03 A processing error was discovered in the 2008 National Health Interview Survey's Sample Adult Public Use file. The processing error created sampling weights for 510 sample adult persons in the 4th quarter that did not undergo a final weight adjustment step for certain age/sex/race/ethnicity groups. NHIS has corrected this error and re-released the file. Read further about this correction.

2010-02-25 ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection:

  • Performed consistency checks.
  • Created variable labels and/or value labels.
  • Created online analysis version with question text.

These data contain multiple weight variables for each part. Users should refer to the User Guide for further information regarding the weights and their derivation. Additionally, users may need to weight the data prior to analysis.


  • The public-use data files in this collection are available for access by the general public. Access does not require affiliation with an ICPSR member institution.

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This study is maintained and distributed by the National Archive of Computerized Data on Aging (NACDA), the aging program within ICPSR. NACDA is sponsored by the National Institute on Aging (NIA) at the National Institutes of Heath (NIH).