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, 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 Office of Management and Budget (OMB) standards for the collection of data on race and ethnicity, to the four race categories specified under the 1977 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 single-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. The vital rates for 1991-1999 calculated using 1990-based postcensal estimates were recalculated using the bridged-race intercensal population estimates for these years and published in NCHS reports. For the 2001-2009 birth and death reports, NCHS used bridged-race postcensal population estimates to calculate birth and death rates. The 2001-2009 vital rates in these reports were calculated using population estimates from the bridged-race postcensal estimates series corresponding with each 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). These procedures were followed for the rates published in the preliminary and final birth and death reports. Vital rates for 2001-2009 will be recalculated using the bridged-race intercensal population estimates for 2001-2009. The revised vital rates for selected birth measures have recently been published. The remaining revised vital statistics rates will be presented in forthcoming NCHS reports.

Newest Data Release

NCHS released the following bridged-race population files on November 17, 2011:

National intercensal estimates of the resident population (i.e., July 1, 2000-July 1, 2009) by single-year of age, sex, bridged-race, and Hispanic origin;
National, State, and County estimates of the resident population for April 1, 2010 by single-year of age, sex, bridged-race, and Hispanic origin; and
State intercensal estimates of the resident population (i.e. July 1, 2000-July 1, 2009) by 5-year age group, sex, bridged-race, and Hispanic origin.

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

Revised intercensal population estimates.

Revised State intercensal estimates of the resident population (i.e. July 1, 2000-July 1, 2009) 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; the revised estimates are likely to differ from the currently available estimates.

County intercensal estimates of the resident population (i.e. July 1, 2000-July 1, 2009) by 5-year age group, sex, bridged race, and Hispanic origin. It is possible that this file will include estimates for the age groups 0, 1-4 years, 15-17 years and 18-19 years.

Note that the currently available national intercensal estimates are not expected to change with the release of the revised intercensal State/County population estimates.

Vintage 2010 postcensal estimates.

National and State Vintage 2010 postcensal estimates of the resident population (i.e., July 1, 2000 - July 1, 2010), by single-year of age(0, 1, 2, ...,85+), sex, bridged race, and Hispanic origin;

County Vintage 2010 postcensal estimates of the resident population (i.e., July 1, 2000 - July 1, 2010), by five-year age groups, sex, bridged race, and Hispanic origin;

National Vintage 2010 postcensal estimates of the resident population (i.e., July 1, 2000 - July 1, 2010), by single-year of age 85-100+, sex, bridged race, and Hispanic origin.

Changes in Census Bureau Estimates Methodology

The Census Bureau revised their population estimation methodology beginning with the Vintage 2007 postcensal series of estimates (see Vintage 2007, Vintage 2008, and Vintage 2009 file documentation for moredetails and references). The Census Bureau believes the new estimation methods represent improvements over previous procedures and results in more accurate population estimates. The net impact of the various 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 2009 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 2009 file documentation for references).

Geographic Codes in the Bridged-Race Population Files

Changes in county/county equivalent geography during the 1990s and 200s have resulted in the formation of a few new counties/county equivalents and the deletion of others. For example, the Vintage 2009 files have population estimates for three new county equivalents (Wrangell Borough, Petersburg Census Area, and Prince of Wales-Hyder Census Area) and do not have estimates for two former county equivalents (Wrangell-Petersburg Census Area and Prince of Wales-Outer Ketchikan Census Area). Vintage 2008 has estimates for two new Alaska entities and does not have estimates for one former entity. The tables below summarize differences in county geography across the various estimates series.

New counties and county equivalents (not on all of the bridged-race population files): 1990-2010

Estimates series	County or county equivalent
Estimates series	Number of counties	Broomfield, CO (08-014)	Hoonah-Angoon Census Area, AK (02-105)	Skagway Municipal., AK (02-230)	Petersburg Census Area, AK (02-195)	Prince of Wales-Hyder Census Area, AK (02-198)	Wrangell City and Borough , AK(02-275)
Intercensal estimates
1990-1999	3,141	--*--	--*--	--*--	--*--	--*--	--*--
Census counts
April 1, 2000	3,141	--*--	--*--	--*--	--*--	--*--	--*--
Postcensal estimates
Vintage 2001	No county estimates on file, only national estimates
Vintage 2002	3,141	X	--*--	--*--	--*--	--*--	--*--
Vintage 2003	3,140	--*--	--*--	--*--	--*--	--*--	--*--
Vintage 2004	3,140	--*--	--*--	--*--	--*--	--*--	--*--
Vintage 2005	3,141	X	--*--	--*--	--*--	--*--	--*--
Vintage 2006	3,141	X	--*--	--*--	--*--	--*--	--*--
Vintage 2007	3,141	X	--*--	--*--	--*--	--*--	--*--
Vintage 2008	3,142	X	X	X-	--*--	--*--	--*--
Vintage 2009	3,143	X	X	X	X	X	X
Postcensal estimates
2000-2009	3,143	X	X	X	X	X	X
Census counts
April 1, 2010	3,143	X	X	X	X	X	X

--*-- County or county equivalent is not on the file.

X County or county equivalent is on the file.

Deleted counties and county equivalents not on all of the bridged-race population files: 1990-2009

Estimates series	County or county equivalent
Estimates series	Number of counties	Clifton Forge County, VA 51-560	Prince of Wales-Outer Ketchikan Census Area, AK 02-201	Skagway-Hoonah-Angoon Census Area, AK 02-232	Wrangell–Petersburg Census Area, AK 02-2j80
Intercensal estimates
1990-1999	3,141	X	X	X	X
Census counts
April 1, 2000	3,141	X	X	X	X
Postcensal estimates
Vintage 2001	No county estimates on file, only national estimates
Vintage 2002	3,141	--*--	X	X	X
Vintage 2003	3,140	--*--	X	X	X
Vintage 2004	3,140	--*--	X	X	X
Vintage 2005	3,141	--*--	X	X	X
Vintage 2006	3,141	--*--	X	X	X
Vintage 2007	3,141	--*--	X	X	X
Vintage 2008	3,142	--*--	X	--*--	X
Vintage 2009	3,143	--*--	--*--	--*--	--*--
Intercensal estimates
2000-2009	3,141	--*--	--*--	--*--	--*--
Census counts
April 1, 2010	3,141	--*--	--*--	--*--	--*--

--*-- County or county equivalent is not on the file.

X County or county equivalent is on the file.

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).

Bridged-Race Estimates Methodology

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

Data Files and Documentation

Release of Bridged-Race Population Estimates

Interactive Databases and Related Resources

Suggested Citation

The suggested citation for the Vintage 2009 postcensal series of estimates is:

National Center for Health Statistics. Postcensal estimates of the resident population of the United States for July 1, 2000-July 1, 2009, by year, county, age, bridged race, Hispanic origin, and sex (Vintage 2009). Prepared under a collaborative arrangement with the U.S. Census Bureau; released June 20, 2010. Available from: www.cdc.gov/nchs/nvss/bridged_race.htm as of July 23, 2010.

Suggested citations for the other estimates series can be found in the corresponding file documentation.

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: