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Bridged-Race Population Estimates for Census 2000


Race data on the 2000 census are not comparable with race data from data systems that continue to collect data using the 1977 Office of Management and Budget (OMB) Standards for the Classification of Federal Data on Race and Ethnicity during the transition to full implementation of the 1997 OMB Standards. For example, states have been implementing the 2003 Standard Birth and Death certificates, which include race and ethnicity items that are compliant with the 1997 OMB Standards, at different times. To date, many state vital certificates are still based on the 1989 standard certificates which collect race and ethnicity data in accordance with the 1977 OMB Standards. Thus, population estimates for 2000 and beyond with race categories comparable to the 1977 categories are needed so that race-specific birth and death rates can be calculated. To meet this need, the National Center for Health Statistics (NCHS), in collaboration with the U.S. Census Bureau, developed methodology to bridge the 31 race groups in Census 2000 to the four single-race categories specified under the 1977 Standards.


Centers for Disease Control and Prevention and U.S. Census Bureau (CDC and Census)

Data Years Available

Postcensal estimates are available for year 2000 and later; intercensal estimates are available for the years 1990-1999.





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NCHS releases bridged-race population estimates of the July 1st resident population of the United States, based on Census 2000 counts, for use in calculating vital rates. These estimates result from "bridging" the 31 race categories used in Census 2000, as specified in the 1997 OMB standards for the collection of data on race and ethnicity, to the four race categories specified under the 1977 standards (Asian or Pacific Islander, Black or African American, American Indian or Alaska Native, White). Many data systems, such as vital statistics, are continuing to use the 1977 OMB standards during the transition to full implementation of the 1997 OMB standards. Postcensal population estimates are estimates made for the years following a census, before the next census has been taken. Postcensal estimates are derived by updating the population enumerated in the census using various measures of population change. Each year following the decennial census, the U.S. Census Bureau produces a series of postcensal estimates that includes estimates for the current data year and revised estimates for earlier years. Estimates for earlier years in a given series are revised to reflect changes in the components of change data sets (for example, a preliminary natality file is replaced with a final natality file). The last year in a series is used to name the series. For example, the Vintage 2002 postcensal series has estimates for July 1, 2000, July 1, 2001, and July 1, 2002 (released 8/1/2003). The Vintage 2003 series has estimates for July 1, 2000, July 1, 2001, July 1, 2002, and July 1, 2003. The July 1, 2000, July 1, 2001, and July 1, 2002 estimates from the Vintage 2002 and Vintage 2003 series differ. Intercensal population estimates are estimates made for the years between two completed censuses and take into account both censuses. Intercensal estimates replace the postcensal estimates previously made for the time period. The 1990-1999 intercensal estimates are based on both the 1990 and the 2000 decennial census counts, and replace the previous postcensal series of estimates.

Population covered

U.S. resident population


The bridging methodology was developed using information from the 1997-2000 National Health Interview Survey (NHIS). The NHIS provides a unique opportunity to investigate multiple-race groups because, since 1982, it has allowed respondents to choose more than one race but has also asked respondents reporting multiple races to choose a primary race. The bridging methodology developed by NCHS involved the application of regression models relating person-level and county-level covariates to the selection of a particular primary race by the multiple-race respondents. Bridging proportions derived from these models were applied by the U.S. Census Bureau to the Census 2000 Modified Race Data Summary file. This application resulted in bridged counts of the April 1, 2000, resident single-race populations for four racial groups: American Indian or Alaska Native, Asian or Pacific Islander, black, and white.

Response rate and sample size


Interpretation Issues