Overview

Race bridging refers to making data collected using one set of race categories consistent with data collected using a different set of race categories, to permit estimation and comparison of race-specific statistics at a point in time or over time. More specifically, race bridging is a method used to make multiple-race and single-race data collection systems sufficiently comparable to permit estimation and analysis of race-specific statistics.

The National Center for Health Statistics releases bridged-race population estimates of the resident population of the United States for use in calculating vital rates. These estimates result from bridging the 31 race categories used in Census 2000 and Census 2010, as specified in the 1997 Office of Management and Budget (OMB) standards for the collection of data on race and ethnicity, to the four race categories specified in the 1977 OMB standards. 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. The bridged-race population estimates are produced under a collaborative arrangement with the U. S. Census Bureau. The bridging methodology is described in the report, "Census 2000 Populations with Bridged Race Categories [PDF - 1.2 MB]" which was published in September 2003 and is available for download from this site.

The bridged-race population estimates are used by NCHS to calculate birth and death rates for data year 2000 and later years, as well as to produce revised birth and death rates for the 1990s and 2000.

NCHS used bridged-race intercensal population estimates to recalculate the vital rates for 1991-1999 which originally were calculated using 1990-based postcensal estimates. The revised rates were published in NCHS reports.
NCHS used bridged-race April 1, 2000 census counts to calculate vital rates in the 2000 birth and death reports.
NCHS used bridged-race postcensal population estimates to calculate vital rates for the 2001-2009 preliminary and final birth and death reports. Vital rates for a given year were calculated using population estimates from the bridged-race postcensal estimates series corresponding with that data year (i.e., vital statistics rates for 2001 were calculated using population estimates from the Vintage 2001 postcensal series, vital rates for 2002 were calculated using estimates from the Vintage 2002 postcensal series, and so forth).
NCHS is using bridged-race intercensal population estimates to recalculate vital rates for 2001-2009 (which were originally calculated using bridged-race postcensal estimates). Some revised vital rates have been published; others are forthcoming.
NCHS is using bridged-race April 1, 2010 census counts to calculate vital rates in the 2010 birth and death reports. The July 1, 2010 bridged-race intercensal population estimates are being used to calculate selected birth measures in the 2010 birth report.

Newest Data Release

NCHS released the Vintage 2011 bridged-race postcensal population files (2010 census-based estimates for July 1, 2010-July 1, 2011) on July 18, 2012:

County Vintage 2011 postcensal estimates of the resident population (i.e., July 1, 2010 - July 1, 2011), by single-year of age(0, 1, 2, ...,85+), sex, bridged race, and Hispanic origin;
National Vintage 2011 postcensal estimates of the resident population (i.e., April 1, 2010 - July 1, 2011), by single-year of age (85, 86, ..., 100+), sex, bridged race, and Hispanic origin.

NCHS expects to release the following additional bridged-race data files in 2012:

Revised intercensal population estimates.

Revised national intercensal estimates of the resident population (i.e. July 1, 2000-July 1, 2010) by single-year of age, sex, bridged-race, and Hispanic origin. The revised estimates differ from the currently available national intercensal estimates. Although the differences are relatively small, some are large enough to change the intercensal population-based vital rates by a tenth (mostly for American Indian and Alaska Native groups and for Asian or Pacific Islander groups).

Revised State intercensal estimates of the resident population (i.e. July 1, 2000-July 1, 2010) by single-year of age, sex, bridged race, and Hispanic origin. These revised estimates by single-year of age will replace the currently available State intercensal estimates by 5-year age group, bridged race, sex, and Hispanic origin. NCHS is reviewing the differences between the revised and currently available State intercensal estimates.

County intercensal estimates of the resident population (i.e. July 1, 2000-July 1, 2010) by single-year of age, sex, bridged race, and Hispanic origin.

Changes in Census Bureau Estimates Methodology

The Census Bureau introduced changes to the estimation methodology used for the Vintage 2007, Vintage 2008, and Vintage 2009 series of postcensal estimates (details and references are provided in the file documentation for these three vintages). The Census Bureau believes the revised estimation methods represent improvements over previous procedures and result in more accurate population estimates. The net impact of the methodological changes was a downward shift of the Vintage 2007 and Vintage 2008 series of postcensal population estimates when compared to those from earlier vintages (primarily due to a downward shift in the net international migration estimates) and an upward shift in the Vintage 2009 estimates compared to the Vintage 2008 estimates.

When producing the Vintage 2006 - Vintage 2010 postcensal series of estimates, the Census Bureau employed adjustments designed to accommodate geographic shifts in the populations of Alabama, Louisiana, Mississippi and Texas that resulted from Hurricanes Katrina and Rita in 2005 (see Vintage 2007 - Vintage 2010 file documentation for references).

Geographic Codes in the Bridged-Race Population Files

County Geography Changes: 1990-2011 [PDF - 36 KB]

County geography changes over time – new counties are created and old counties are deleted or their boundaries are modified. Changes that have occurred in the county FIPS codes on the bridged-race population files (as a result of county geography changes that affected population estimates for 1990- 2011) are detailed in file documentation and in “County Geography Changes: 1990-2011”.

Bridged-Race Estimates Methodology

United States Census 2000 Population with Bridged Race Categories [PDF - 5.6 MB] (9/2003)

Estimates for persons 85 to 100+ years of age

National bridged-race postcensal estimates of the resident population of the United States by year, single-year of age (85, 86, …, 100+ years), bridged-race category (White, Black or African American, American Indian or Alaska Native, Asian or Pacific Islander), Hispanic origin (not Hispanic or Latino, Hispanic or Latino), and sex are available for Vintage 2003-Vintage 2011 by special request.

Downloadable Data Files and Documentation

Release of Bridged-Race Population Estimates

In response to the need for bridged estimates by a wide range of users, NCHS makes the bridged-race population estimates available for download from this web site (see Data Files and Documentation). The report detailing the bridging methodology, “United States Census 2000 Population with Bridged Race Categories”, also is available for download from this site (see Bridged-Race Estimates Methodology).

Interactive Databases and Related Resources

Suggested Citation

Suggested citation for the bridged-race April 1, 2010 census counts:

National Center for Health Statistics. Estimates of the April 1, 2010 resident population of the United States, by county, single-year of age (0, 1, 2, …, 85 years and over), bridged race, Hispanic origin, and sex. Prepared under a collaborative arrangement with the U.S. Census Bureau. Available from: http://www.cdc.gov/nchs/nvss/bridged_race.htm as of November 17, 2011, following release by the U.S. Census Bureau of the unbridged April 1, 2010 census counts on November 3, 2011

Suggested citation for the bridged-race Vintage 2011 postcensal series of estimates:

National Center for Health Statistics. Postcensal estimates of the resident population of the United States for July 1, 2010-July 1, 2011, by year, county, single-year of age (0, 1, 2, .., 85 years and over), bridged race, Hispanic origin, and sex (Vintage 2011). Prepared under a collaborative arrangement with the U.S. Census Bureau. Available from: http://www.cdc.gov/nchs/nvss/bridged_race.htm as of July 18, 2012, following release by the U.S. Census Bureau of the unbridged Vintage 2010 postcensal estimates by 5-year age group on May 17, 2012.

Suggested citations for each of the bridged-race population files are provided in the file documentation corresponding to each file.

Comments and Questions

NCHS would appreciate receiving feedback on the usefulness of the bridged-race estimates as well as notification of any problems that have been identified. Comments or questions about the estimates may be sent via e-mail to: PopEst@cdc.gov

Tabulated Data

The following tables (as Excel spreadsheets) showing bridged and enumerated population counts for 2000 and the 1990-based July 1, 2000, postcensal population estimates previously used by NCHS to calculate vital rates are available for download: