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Documentation for Bridged-Race Vintage 2009
(July 1, 2000 - July 1, 2009)
Postcensal Population Estimates for Calculating Vital Rates

On July 23, 2010, the National Center for Health Statistics released the Bridged-race Vintage 2009 postcensal population file.

The Vintage 2009 bridged-race postcensal population estimates files contain estimates of the resident population of the United States as of July 1, 2000 to July 1, 2008, by county, single-year of age (0, 1, 2,..., 85 years and over), 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 (1). The estimates on this file are based on Census 2000 and result from bridging the Vintage 2008 postcensal estimates with 31 race groups (the 31 race groups used in Census 2000 in accordance with 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 OMB standards (2,3).

Source of the Estimates

The Vintage 2009 bridged-race postcensal estimates were produced by the Population Estimates Program of the U.S. Census Bureau in collaboration with the National Center for Health Statistics (NCHS). This file was released by the Census Bureau on June 20, 2010 and by NCHS on July 23, 2010.

Changes in Estimates Methodology Implemented for Vintage 2009

The Vintage 2009 postcensal population estimates reflect four major improvements in the estimates methodology:

  1. changes in the estimation of net international migration,
  2. changes in the estimation of the distribution of deaths to people aged 70 and older by age, sex, race, and Hispanic origin,
  3. changes in the estimation of domestic migration of the population age 65 years and older, and
  4. changes in the estimation of the age distribution of migration to and from counties (4, 5).
Adjustments for Hurricanes Katrina and Rita were accomplished using a different approach than used for Vintage 2006-Vintage 2008 (4, 6). At the national level, the result of the various methodologic changes is an upward shift of the Vintage 2009 postcensal population estimates when compared to those from the Vintage 2008 series. At the State and county level, some race and age groups experienced substantial changes (comparison of July 1, 2008 estimates from the Vintage 2008 series with the July 1, 2008 and July 1, 2009 estimates from the Vintage 2009 series).

Vintage 2008 Postcensal Population Estimates

Vintage 2008 postcensal population estimates reflect three major improvements in the estimates methodology (7, 8). Improvements include these changes:

  1. the estimation of net international migration,
  2. the incorporation of accepted challenges and special censuses into the national population estimates, and
  3. the imputation of the race and Hispanic origin for births. These methodology changes go beyond the extensive methodology changes implemented for the Vintage 2007 estimates (9). The net impact of the various methodologic changes is a downward shift of the Vintage 2008 postcensal population estimates when compared to those from the Vintage 2007 series; the Vintage 2007 postcensal estimates also reflected a downward shift when compared to the 2006 estimates.

    Hurricanes Katrina and Rita Impact on Vintage 2006-Vintage 2009 Estimates

    For Vintage 2006-Vintage 2008, the Census Bureau adjusted the population estimates for Alabama, Louisiana, Mississippi and Texas (for 2006 and later) to accommodate geographic shifts in the populations that resulted from Hurricanes Katrina and Rita in 2005 (10, 11, 12) These adjustments were not used for the Vintage 2009 estimates because the updated methodology and data used to produce the Vintage 2009 estimates reflected the impact of the hurricanes (6).

    Geographic Codes in the Bridged-Race Population Files

    Some of the population estimates series have slightly different sets of counties/county equivalents due to changes in county geography (13). 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. Vintage 2002, Vintage 2005, Vintage 2006, and Vintage 2007 have estimates for the same 3,141 counties and county equivalents; Vintage 2003 and Vintage 2004 have estimates for the same 3,140 counties and county equivalents. The intercensal files and the April 1, 2000 files have estimates for the same set of entities (note that this set differs slightly from all of the sets associated with the postcensal estimates series). 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: 1990-2009
    Series Number of counties County or County Equivalent
      Broomfield, CO
    (08014)
    Hoonah-Angoon Census Area, AK
    (02105)
    Skagway Municipality, AK
    (02230)
    Petersburg Census Area, AK
    (02195)
    Prince of Wales-Hyder Census Area, AK
    (02198)
    Wrangell City and Borough, AK
    (02275)
    Intercensal estimates
    1990 -1999 3,141 --*-- --*-- --*-- --*-- --*-- --*--
    Census counts 2000
    April 1, 2000 3,141 --*-- --*-- --*-- --*-- --*-- --*--
    Postcensal estimates
    Vintage 2001, 2000-2001None, only national estimates.
    Vintage 2002, 2000-20023,141 X --*-- --*-- --*-- --*-- --*--
    Vintage 2003, 2000-20033,140 --*-- --*-- --*-- --*-- --*-- --*--
    Vintage 2004, 2000-20043,140 --*-- --*-- --*-- --*-- --*-- --*--
    Vintage 2005, 2000-20053,141 X --*-- --*-- --*-- --*-- --*--
    Vintage 2006, 2000-20063,141 X --*-- --*-- --*-- --*-- --*--
    Vintage 2007, 2000-20073,141 X --*-- --*-- --*-- --*-- --*--
    Vintage 2008, 2000-20083,142 X X X --*-- --*-- --*--
    Vintage 2009, 2000-20093,143 X X X X X X
       --*--    County or county equivalent is not on the file.
         X      County or county equivalent is on the file.

    Specific details for new counties:

    • Broomfield County, Colorado (FIPS code 08014) was created effective November 15, 2001 from parts of four Colorado counties: Adams, Boulder, Jefferson, and Weld. There are estimates for this county on some, but not all, of the bridged-race files. Note that data for Broomfield County do not appear on NCHS birth or mortality files until data year 2003.

    • Hoonah-Angoon Census Area, Alaska (FIPS code 02105). The Hoonah-Angoon Census Area was created from the remainder of the former Skagway-Hoonah-Angoon Census Area (FIPS code = 02232) when Skagway Municipality (FIPS code = 02230) was created effective June 20, 2007; population: 2,574. This county equivalent appears only on the Vintage 2008 files. Note that no data for Hoonah-Angoon Census Area appear on NCHS birth and mortality files.

    • Petersburg Census Area, Alaska(FIPS code 02195). Petersburg Census Area was created from part of the former Wrangell-Petersburg Census Area (FIPS code 02280) effective June 1, 2008; population: 4,260. This county equivalent appears only on the Vintage 2009 files. Note that no data for this Census Area appear on NCHS birth and mortality files.

    • Prince of Wales-Hyder Census Area, Alaska (FIPS code 02198). Prince of Wales-Hyder Census Area was created from remainder of the former Prince of Wales-Outer Ketchikan Census Area (FIPS code 02201) after part (Outer Ketchikan) was annexed by Ketchikan Gateway Borough (FIPS code 02130) effective May 19, 2008 and another part was included in the new Wrangell Borough (effective June 1, 2008); population: 6,115. This county equivalent appears only on the Vintage 2009 files. Note that no data for this Census Area appear on NCHS birth and mortality files.

    • Skagway Municipality, Alaska (FIPS code 02230). Skagway Municipality was created from part of the former Skagway-Hoonah-Angoon Census Area (FIPS code 02232) effective June 20, 2007; boundaries are identical to the Skagway census subarea; population: 862. The remainder of the former Skagway-Hoonah-Angoon Census Area was established as the new Hoonah-Angoon Census Area (FIPS code 02105). This county equivalent appears only on the Vintage 2008 files. Note that no data for Skagway Municipality appear on NCHS birth and mortality files.

    • Wrangell City and Borough, Alaska (FIPS code 02275). Effective June 1, 2008, Wrangell City and Borough was created from part of Wrangell-Petersburg Census Area (FIPS code 02280) and part of Prince of Wales-Outer Ketchikan Census Area (FIPS code 02201); population: 2,448. This county equivalent appears only on the Vintage 2009 files. Note that no data for Wrangell Borough appear on NCHS birth and mortality files.

    Deleted counties and county equivalents not on all of the bridged-race population files: 1990-2009
    County or County Equivalent
    Estimates Series Number of Counties Clifton Forge County, VA
    (51560)
    Prince of Wales-Outer Ketchikan Census Area, AK
    (02201)
    Skagway-Hoonah-Angoon Census Area, AK
    (02232)
    Wrangell–Petersburg Census Area, AK
    (02280)
    Intercensal estimates
    1990 - 1999 3,141 X X X X
    Census counts
    April 1, 2000 3,141 X X X X
    Postcensal estimates
    Vintage 2001None, only national estimates.
    Vintage 20023,141 --*-- X X X
    Vintage 20033,140 --*-- X X X
    Vintage 20043,140 --*-- X X X
    Vintage 20053,141 --*-- X X X
    Vintage 20063,141 --*-- X X X
    Vintage 20073,141 --*-- X X X
    Vintage 20083,142 --*-- X --*-- X
    Vintage 20093,143 --*-- --*-- --*-- --*--
       --*--    County or county equivalent is not on the file.
         X      County or county equivalent is on the file.

    Specific details for deleted counties:

    • Clifton Forge, Virginia (FIPS code 51560). On July 1, 2001, Clifton Forge city, Virginia, formerly an independent city, merged with Alleghany county (FIPS code=51005). There are no estimates for this county on the bridged-race postcensal population files. Note that data for Clifton Forge city appear on NCHS birth and mortality files prior to data year 2003; beginning with the 2003 data year, no data for Clifton Forge city appear on the birth and death files.

    • Prince of Wales - Outer Ketchikan Census Area, Alaska (FIPS code 02201). Part of this area (Outer Ketchikan) was annexed by Ketchikan Gateway Borough (FIPS code 02130), part was included in the new Wrangell City and borough (FIPS code 02275), and the remainder was renamed Prince of Wales-Hyder Census Area (FIPS code 02198). This county equivalent appears on the bridged-race files prior to Vintage 2009 (except for Vintage 2001 for which no county-level data are available). Note that data for this Census Area Hoonah appear on NCHS birth and mortality files for 1994 – present.

    • Skagway-Hoonah-Angoon Census Area, Alaska (FIPS code 02232). Effective June 20, 2007, Skagway-Hoonah-Angoon Census area was split to create Skagway Municipality (FIPS = 02230) and Hoonah-Angoon Census Area (FIPS code = 02105). This county equivalent appears on the bridged-race files prior to Vintage 2008 (except for Vintage 2001 for which no county-level data are available). Note that data for Skagway-Hoonah-Angoon Census Area appear on NCHS birth and mortality files for years 1994 - the present.

    • Wrangell-Petersburg Census Area, Alaska (FIPS code 02280). Effective June 1, 2008, Wrangell-Petersburg Census Area was split to create part of Wrangell City and Borough (FIPS code 02275) and all of Petersburg Census Area (FIPS code 02195). This county equivalent appears on the bridged-race files prior to Vintage 2009 (except for Vintage 2001 for which no county-level data are available). Note that data for Wrangell-Petersburg Census Area appear on NCHS birth and mortality files for 1994 – present.

    Race Bridging Background

    What is race bridging? 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.

    OMB’s 1977 and 1997 standards on race and ethnicity:  In 1997, OMB issued "Revisions to the Standards for the Classification of Federal Data on Race and Ethnicity," which supersedes the 1977 "Statistical Policy Directive 15, Race and Ethnic Standards for Federal Statistics and Administrative Reporting" (2, 3). Both documents specify rules for the collection, tabulation, and presentation of race and ethnicity data within the Federal statistical system. The race categories specified in both standards represent a social-political construct and are not anthropologically or biologically based. The revised standards increased the minimum number of race categories to be used by Federal agencies from four (White, Black, American Indian or Alaska Native, and Asian or Pacific Islander) to five (White, Black or African American, American Indian or Alaska Native, Asian, and Native Hawaiian or Other Pacific Islander). In addition, the revised standards require Federal data collection programs to allow respondents to select more than one race category when responding to a query on their racial identity. This provision means that under the revised standards there are potentially 31 race groups (5 single-race and 26 multiple-race), depending on whether an individual selects one, two, three, four, or all five of the race categories.

    Why race bridge? During the transition to full implementation of the 1997 standards (see paragraph below), these two different standards for the collection of race and ethnicity data are both being used, creating incomparability across data systems. Further, within a given data system, the change in the race standards results in incomparability across time, thus making it difficult to perform trend analyses. The OMB recognized that race-bridging approaches would be needed to make race data collected under the 1997 standards comparable to race data collected under the 1977 standards. Therefore, the OMB issued "Provisional Guidance on the Implementation of the 1997 Standards for Federal Data on Race and Ethnicity" (14). The guidance document contains a detailed discussion of various bridging methods.

    Why does NCHS use bridged-race population estimates? Vital rates are based on information obtained from vital records collected through the state-based Vital Statistics Cooperative Program (numerators) and population estimates derived from the U.S. Census (denominators). Because of differences in the timing of implementation of the 1997 standards, beginning with the 2000 data year, the numerators and denominators of vital rates have incompatible race data. The question on race on the 2000 census was based on the revised OMB standards and so allowed respondents to select more than one race category. As a result, population estimates for 2000 and beyond have five single-race categories and up to 26 multiple-race categories. Implementation of the 1997 standards within the Vital Statistics Cooperative System started in 2003, on an individual state basis, and is expected to proceed slowly as states implement revised birth and death certificates which incorporate the 1997 OMB standards. As of 2009, 19 states had not revised the race question on their death certificate and 17 had not revised it on their birth certificate and were still collecting race data using the 1977 race categories. Therefore, at this time, the calculation of post-2000 race-specific birth and death rates requires population estimates with the 1977 race categories. For this reason and because of the need for birth and death trend data, NCHS continues to compute rates using the 1977 OMB race categories. When a sufficient number of states have adopted the revised birth and death certificates, rates will be presented using population estimates that comply with the 1997 standards.

    Specifics about NCHS Use of Bridged-Race Population Estimates NCHS publishes national (and some state) birth and death rates on an annual basis. NCHS uses the bridged-race postcensal population estimates to calculate birth and death rates. Vital rates for a given data year are calculated using bridged-race population estimates from the bridged-race estimates series corresponding with that year. For example, vital 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. Vital rates for postcensal data years are not recalculated using updated postcensal estimates. Rather, NCHS revises rates published for postcensal years only once intercensal population estimates become available. Thus, the vital rates for 1991-1999, which originally were calculated using 1990-based postcensal population estimates, have been recalculated using the bridged-race intercensal population estimates for 1991-1999.

    NCHS Regression Bridging Method

    Bridging methodology developed by NCHS bridges the multiple-race group population counts to single-race categories (15, 16). Information from the pooled 1997-2000 National Health Interview Survey was used to develop the bridging methodology. Regression models with person-level and county-level covariates were used to generate the probability of selecting each single-race category possible for a multiple-race group. The probabilities generated from the fitted regression models are referred to as the NHIS bridging proportions. The Census Bureau applied the NHIS bridging proportions generated by NCHS to the Census 2000 Modified Race Data Summary file (17). This application resulted in a bridged population count for each of the four single-race categories (White, Black or African American, American Indian or Alaska Native, and Asian or Pacific Islander) by county, single-year of age, Hispanic origin group, and sex, for April 1, 2000. Annually, the bridging proportions are applied to the latest vintage of postcensal estimates with 31 race groups (the 31 race groups used in Census 2000 in accordance with the 1997 OMB standards) to obtain the bridged-race population estimates for the four single-race categories. The bridging methodology is described in detail in the report, "United States Census 2000 Population with Bridged Race Categories" (13).

    Bridged-race Postcensal Population Estimates

    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 resident population enumerated in the decennial census using various measures of population change. The components of population change used in the derivation of the postcensal estimates include: births to U.S. resident women, deaths to U.S. residents, net international immigration, net movement of U.S. Armed Forces and civilian citizens of the U.S, and migration within the U.S. The Census Bureau annually produces a series of postcensal estimates that includes estimates for the current data year and revised estimates for earlier years. 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. 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. Estimates for earlier years in a given series are revised to reflect

    1. changes in the components of population change data sets (for example, a preliminary natality file is replaced with a final natality file);
    2. challenges to the population estimates; and
    3. changes in the estimation methodology.
    Because of the revisions made to the estimates in each series, pulling estimates from several vintages rather than from a single vintage may introduce discontinuities.

    The Census Bureau annually produces a postcensal series of estimates of the resident population of the United States with 31 race groups (in accordance with the 1997 OMB standards). The Census 2000 Modified Race Data Summary File serves as the base data for these post-2000 postcensal series (17). Under a collaborative arrangement with NCHS, the Population Estimates Program of the U.S. Census Bureau applies the NHIS bridging proportions to the 31-race postcensal population estimates to produce the bridged-race postcensal estimates (estimates for the four single-race categories: White, Black or African American, American Indian or Alaska Native, and Asian or Pacific Islander).

    Variance of Bridged-Race Population Estimates

    Population estimates generally are assumed to be fixed and do not contribute to the variance of rates. However, this is not true for bridged-race population estimates. Although efforts were made to use the best available data and methods to produce the bridged-race estimates, the modeling process introduces error into the estimates. The potential for error will be greatest for the smallest population groups, particularly the smaller race groups and county level estimates. Methodology to compute variances for bridged-race population estimates has been developed (18).

    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 the web site "U.S. Populations with Bridged Race Categories" (http://www.cdc.gov/nchs/nvss/bridged_race.htm) and also through CDC WONDER online databases (http://wonder.cdc.gov]. The report detailing the bridging methodology, "United States Census 2000 Population with Bridged Race Categories," also is available for download (15).

    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

    Suggested Citation

    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 May 20, 2010. Available from: http://www.cdc.gov/nchs/nvss/bridged_race.htm as of July 23, 2010.

    References

    1. 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, 2009. http://www.cdc.gov/nchs/nvss/bridged_race.htm as of July 23, 2010. (Available at http://www.cdc.gov/nchs/nvss/bridged_race.htm.)
    2. Office of Management and Budget. Revisions to the standards for the classification of Federal data on race and ethnicity. Federal Register 62FR58781-58790, October 30, 1997. (Available here.)
    3. Office of Management and Budget. Race and ethnic standards for Federal statistics and administrative reporting. Statistical Policy Directive 15, May 12,1977. (Available here.)
    4. U.S. Census Bureau. Vintage 2009 estimates: release notes. 2010. (Available here.)
    5. U.S. Census Bureau. Methodology for the United States resident population estimates by age, sex, race, and Hispanic origin (Vintage 2009): April 1, 2000 to July 1, 2009. 2010. (Available here.)
    6. U.S. Census Bureau. Special processing procedures for the areas affected by Hurricanes Katrina and Rita (Vintage 2009): April 1, 2000 to July 1, 2009. 2010. (Available here.)
    7. U.S. Census Bureau. Vintage 2008 estimates: release notes. 2009. (Available here.)
    8. U.S. Census Bureau. Methodology for the United States resident population estimates by age, sex, race, and Hispanic origin (Vintage 2008): April 1, 2000 to July 1, 2008. 2009. (Available here.)
    9. U.S. Census Bureau. Methodology for the United States resident population estimates by age, sex, race, and Hispanic origin (Vintage 2007): April 1, 2000 to July 1, 2007. 2008. (Available here.)
    10. U.S. Census Bureau. Special processing procedures for the areas affected by Hurricanes Katrina and Rita: (Vintage 2008): April 1, 2000 to July 1, 2008. 2009. (Available here or from http://www.census.gov/popest/topics/methodology/2008-hurr-spcl-meth.html).
    11. U.S. Census Bureau. Special processing procedures for the areas affected by Hurricanes Katrina and Rita: (Vintage 2007): April 1, 2000 to July 1, 2007. 2008. (Available here or from http://www.census.gov/popest/topics/methodology/2007-hurr-spcl-meth.html).
    12. U.S. Census Bureau. Special population estimates for impacted counties in the Gulf Coast Area. 2008. (Available from http://www.census.gov/newsroom/emergencies/additional/impacted_gulf_estimates.html).
    13. U.S. Census Bureau. Substantial changes to counties and county equivalent entities: 1970-present. (Available from http://www.census.gov/geo/www/tiger/ctychng.html).
    14. Office of Management and Budget. Provisional guidance on the implementation of the 1997 standards for the collection of Federal data on race and ethnicity. December 15, 2000. http://www.Whitehouse.gov/omb/inforeg/r&e_guidance2000update.pdf. (Also available here.)
    15. Ingram DD, Parker JD, Schenker N, Weed JA, Hamilton B, Arias E, Madans JH. United States Census 2000 population with bridged race categories. Vital Health Stat 2 (135). Hyattsville, Maryland: National Center for Health Statistics. 2003. (Available here.)
    16. Parker JD, Schenker N, Ingram DD, Weed JA, Heck KE, Madans JH. Bridging between two standards for collecting information on race and ethnicity: an application to Census 2000 and vital rates. Public Health Reports 119 (2), p. 192-205. 2004. (Available here.)
    17. U.S. Census Bureau. Census 2000 modified race data summary file. Released September 2002. (Data available at http://www.census.gov/popest/archives/files/MR-CO.txt and documentation available here.)
    18. Schenker, N (2003). "Assessing variability due to race bridging: application to Census counts and vital rates for the Year 2000," J American Statistical Association, 98, 818-828. 2003. (Available at http://www.jstor.org/stable/30045333.)

    For file layout information, please refer to http://www.cdc.gov/nchs/nvss/bridged_race.htm.


    Source:

    Documentation for bridged-race postcensal Vintage 2009 population estimates for July 1, 2000-July 1, 2009, which was released on July 23, 2009 is on the internet at ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/Datasets/NVSS/bridgepop/2009/DocumentationBridgedPostcenV2009.pdf.




This page last reviewed: Sunday, August 29, 2010
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