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Bridged-race Population Estimates


Starting in the 2000 decennial census, the U.S Census Bureau has used the 1997 Office of Management and Budget (OMB) revised standards for the classification of Federal data on race and ethnicity. Thus, race data on the 2000 and 2010 census are not comparable with race data from data systems that continue to collect data using the 1977 OMB standards. The 1977 standards specified four single-race categories: American Indian or Alaska Native, Asian or Pacific Islander, black, and white. The 1997 standards required that Federal data collection programs allow respondents to select one or more race categories when responding to a query on their racial identity. This provision means that there are potentially 31 race groups, depending on whether an individual selects one, two, three, four, or all five of the race categories. For comparability, the National Center for Health Statistics (NCHS), in collaboration with the U.S. Census Bureau, developed methodology to bridge the race groups in Census 2000 and 2010 to the four single-race categories specified under the 1977 standards. Even though Federal programs were to fully implement the revised standards by January 1, 2003, the transition from the 1977 to the 1997 OMB standards has been uneven. Federal systems which rely on information obtained from vital records through state-based programs, such as the National Vital Statistics System, have not yet been able to fully implement the 1997 standards. For example, the U.S. standard birth and death certificates were revised in 2003 to include the 1997 OMB standards. However, as of 2011, 41 states, New York City, and the District of Columbia had adopted the 2003 U.S. standard birth certificate, and 36 states, New York City, and the District of Columbia had adopted the 2003 U.S. standard death certificate.

Centers for Disease Control and Prevention, National Center for Health Statistics and U.S. Census Bureau
Data Years Available: 
July 1 postcensal estimates are available for year 2011 and later; intercensal estimates are available for the years 2001-2009; census counts are used for the years 2000 and 2010.
Mode of Collection: 
Selected Content: 
NCHS releases bridged-race population estimates of the July 1st resident population of the United States, based on Census 2000 and 2010 counts, for use in calculating vital rates. 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. 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 2001-2009 intercensal estimates are based on both the 2000 and the 2010 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 and April 1, 2010 resident single-race populations for the four racial groups specified in the 1977 OMB standards.

Response Rates and Sample Size: 
Interpretation Issues: 

Ingram DD, Parker JD, Schenker N, Weed JA, Hamilton B, Arias E, Madans JH. United States Census 2000 population with bridged race categories. National Center for Health Statistics. Vital Health Stat 2(135). 2003. Available at:

Bridged-race population estimates are available from: