United States Census 2000 population with bridged race categories.

TLDR

The report documents NCHS methods for converting Census 2000 multiple‑race resident counts into single‑race categories and outlines how these bridged estimates will be applied to future postcensal population data. The authors built regression models using 1997‑2000 NHIS data that incorporate person‑ and county‑level covariates to generate allocation probabilities, which were applied to Census 2000 counts to produce bridged single‑race estimates that inform birth and death rates and can be updated with future data. Bridging increased national counts by 12.0% for AIAN, 5.0% for API, 2.5% for Black, and 0.5% for White, with greater regional variation observed compared to national totals.

Abstract

The objectives of this report are to document the methods developed at the National Center for Health Statistics (NCHS) to bridge the Census 2000 multiple-race resident population to single-race categories and to describe the resulting bridged race resident population estimates.Data from the pooled 1997-2000 National Health Interview Surveys (NHIS) were used to develop models for bridging the Census 2000 multiple-race population to single-race categories. The bridging models included demographic and contextual covariates, some at the person-level and some at the county-level. Allocation probabilities were obtained from the regression models and applied to the Census Bureau's April 1, 2000, Modified Race Data Summary File population counts to assign multiple-race persons to single-race categories.Bridging has the most impact on the American Indian and Alaska Native (AIAN) and Asian or Pacific Islander (API) populations, a small impact on the Black population and a negligible impact on the White population. For the United States as a whole, the AIAN, API, Black, and White bridged population counts are 12.0, 5.0, 2.5, and 0.5 percent higher than the corresponding Census 2000 single-race counts. At the sub-national level, there is considerably more variation than observed at the national level. The bridged single-race population counts have been used to calculate birth and death rates produced by NCHS for 2000 and 2001 and to revise previously published rates for the 1990s, 2000, and 2001. The bridging methodology will be used to bridge postcensal population estimates for later years. The bridged population counts presented here and in subsequent years may be updated as additional data become available for use in the bridging process.