N C H S - N H I S - Race and Hispanic Origin Information home page

National Health Interview
Survey (NHIS)
Celebrating the First 50 years:
1957 - 2007

Welcome to the
National Health Interview Survey
Race and Hispanic Origin Information home page

The purpose of this site is to provide users of the National Health Interview Survey (NHIS) with in-depth information on race and Hispanic origin, two of the most important demographic variables that are collected in the survey. Here you will find details on race and Hispanic origin data from the NHIS, including the wording of race and Hispanic origin questions from the NHIS, a brief history of race and Hispanic origin data collection in the survey, explanations of the editing and imputation process for the race and Hispanic origin data, frequently asked questions on the NHIS race and Hispanic origin data, and links to important information about collecting race and Hispanic origin data in federal surveys.

We encourage NHIS data users to visit this site frequently, as we will post updates and new information. If you have any comments or questions about the NHIS race and Hispanic origin data or about this site, please send them to the NHIS Listserv.

The National Health Interview Survey (NHIS) is one of the major data collection systems of the National Center for Health Statistics (NCHS). In order to provide the broadest possible perspective on the health data obtained in the survey, the NHIS collects information on the sociodemographic characteristics of respondents, such as age, race, Hispanic origin, sex, education, income, employment, family size and relationships, and geographic region of residence. Demographic characteristics are collected primarily because they provide a context for the health data collected in the survey, and because they help to explain interrelated trends in the survey data. Inequalities in health status and access to care - as well as the unequal burden of morbidity and mortality - for some racial and ethnic groups in the United States have made race and Hispanic origin among the most important demographic characteristics of interest to users of the NHIS.

For almost 20 years, the NHIS collected information on the race and Hispanic origin of its respondents, following guidelines set forth by the Office of Management and Budget (OMB) in a policy known as OMB Directive 15 (1). In response to the changing demographics of the U.S. population and the growing need of persons with multiple racial heritages to indicate this on the Decennial Census and federal surveys, the OMB began a review of these guidelines following the 1990 Census. After an extensive period of research and public commentary, the OMB issued new standards for race and Hispanic origin data collection in the federal statistical system in October 1997 (2). The new standards included provisions for the creation of two new race categories – Asian, and Native Hawaiian and other Pacific Islander – and for the placement of Hispanic origin questions before race questions when the questions are asked separately. It also included a provision permitting respondents to the Census and federal surveys to select more than one group when answering questions on race. The changes were fully implemented in the 1999 NHIS.

The NHIS has collected respondent-reported race and Hispanic origin data on the survey since 1976, and has allowed respondents to the survey to indicate more than one race since that time, although this information was collected only for adults from 1976 through 1981 (3). Beginning in 1982 through the present, race and Hispanic origin data have been collected for household members of all ages. Interviewer-observed race was also collected for survey respondents from 1975-1996, and proxy reporting of race by the household respondent has occurred over the course of the NHIS’ history of collecting race and Hispanic origin data. Over time, there has also been considerable variation in the way that race and Hispanic origin questions have been asked in the survey, as well as variation in the placement of the questions in the questionnaire. Currently, the NHIS contains two questions on Hispanic origin (whether or not the respondent is Hispanic/Latino, and if so, the type of Hispanic/Latino origin) and two questions on race (race group(s) reported by the respondent, and if more than one, which group the respondent considers to be the one that best describes the person). A complete history of race and ethnicity data collection in the NHIS, including information about race and Hispanic origin question wording, placement, and data collection procedures for 1975-2006, can be found here. The draft 2006 race and Hispanic origin questions are located in the Household Composition section of the NHIS, beginning with question number HHC.170.

Race and Hispanic origin data are edited in the Division of Health Interview Statistics (DHIS) on a quarterly basis to produce the variables that appear on our data files. When the raw data are received by DHIS from the U.S. Bureau of the Census (which administers the NHIS), responses that do not initially match any of the existing categories are back-coded where possible. After a basic check for valid responses, race and Hispanic origin recodes are created based on specifications developed by NHIS staff. Figures 1-3 illustrate how the raw data variable names are created from the questionnaire items (Figure 1), how the Hispanic origin recodes are derived (Figure 2), and how the race recodes are derived (Figure 3). Additional details about the race and Hispanic origin editing can be found in Appendix II of the 2004 Survey Description Document.

The NHIS made major changes to its editing procedures in the 2003 data year. Beginning with the 2003 NHIS, “Other race” is no longer coded as a separate race response. Any responses that fall into this category are treated as missing, and the race is imputed if this is the only race response (see the paragraph on imputation below). In cases where “Other race” is mentioned along with one or more OMB race groups, the “Other race” response is dropped and the OMB race group information is retained. These procedures are consistent with the methods used to edit the Modified Race Data summary file (MRD), created by the U.S. Bureau of the Census. More information on the MRD can be found below under “Links to U.S. Bureau of the Census information”.

In the 2000 survey year, the NHIS began implementation of hot-deck imputation of race and Hispanic origin, in order to improve the overall quality of the data. Similar to the editing procedures, the imputation is done in DHIS, and the procedures used are based on methods developed by the U.S. Bureau of the Census. Race and Hispanic origin are first imputed from data on other household members, if available. If not, race and Hispanic origin are imputed from data on members of other households within a small geographic area. Figure 4 illustrates how the imputation of race and Hispanic origin are done in the NHIS.

Along with the information included on this site, additional material is included each year in Appendix II of the NHIS Survey Description Document (SDD) to aid analysts in using the NHIS race and Hispanic origin data. This information includes a description of the variables on the public use file for that survey year, as well as detailed information on the editing and imputation procedures used in processing the data. Appendix II of the SDD also includes sample SAS code for merging race variables across data years and using imputation flags. The 2005 SDD is currently available, and we will update the links to the 2006 SDD as soon as it is available. Users are advised to review the documentation carefully, since variable names sometimes change. This site will also alert data users to any major changes in the data.

Because of NCHS data confidentiality rules, we cannot release data for small population groups, such as Native Hawaiian and Other Pacific Islander or the multiple race groups, on our public use data files. Analysts who wish to include these groups in their data analyses may submit a proposal to use the NCHS Research Data Center (RDC).

To aid users in tracking how variable names have changed over time, a table is available that shows variable name changes for the 1997-2006 survey years, as well as a brief description of the reason for the change. Also, some of the terminology used on this site and in the tables and figures may be unfamiliar to our data users. A glossary of terms is included to assist users in understanding both the terms that are used and the context in which they are used in relation to NHIS race and Hispanic origin data. Some frequently asked questions and their answers are also provided for our users.

We hope that users will provide feedback on this site, and we will regularly update the FAQs to reflect data changes, NCHS policy changes, and input from our users.

Important links to information on race and ethnicity from the OMB and the Census Bureau

Appendix A, Standards for Maintaining, Collecting, and Presenting Federal Data on Race and Ethnicity

Appendix B, Guidance on Aggregation and Allocation of Data on Race for Use in Civil Rights Monitoring and Enforcement

1. Office of Management and Budget. Standards and guidelines for federal statistics: race and ethnic standards for federal statistics and administrative reporting. Federal Register, 1977; Circular No A48, Section 7H, Exhibit F.

2. Office of Management and Budget. Revisions to the standards for the classification of federal data on race and ethnicity. Federal Register, 1997; 62(210): 58782-58790.

3. Kovar MG, Poe GS. The National Health Interview Survey Design, 1973-1984, and Procedures, 1975-1983. Vital and Health Statistics 1(18), 1985.