Census and PolicyMap: Racial and Ethnic Segregation
| Details | Theil’s H index |
|---|---|
| Topics | Demographics, race, ethnicity, segregation |
| Source | American Community Survey, PolicyMap |
| Years Available | 2009-2013, 2014-2018, 2019-2023 |
| Geographies | Block group, tract, county |
| Public Edition or Subscriber-only | Public Edition |
| Download Available | yes |
| For more information | https://www.census.gov/programs-surveys/acs https://www2.census.gov/programs-surveys/demo/about/housing-patterns/multigroup_entropy.pdf |
Description:
PolicyMap calculated Theil’s H index of segregation using the U.S. Census Bureau’s American Commmunity Survey. For this index, PolicyMap used a total of 8 non-overlapping racial and ethnic categories provided by the US Census Bureau. These categories included the ethnic category Hispanic and the following 7 Non-Hispanic racial categories: White, African American, American Indian or Alaska native, Asian, Native Hawaiian or Pacific Islander, some other race, and two or more races.
Theil’s H is an index ranging from 0 to 1 that estimates the extent to which racial and ethnic groups are evenly distributed in a sub-area as compared to a larger area. Values approaching 0 suggest that sub-areas have a composition similar to the larger area (i.e., even distribution, less segregation) and values approaching 1 suggest that the racial and ethnic composition of sub-areas within a larger area deviates from the larger area (i.e., non-uniform distribution, more segregation). On PolicyMap, sub-areas are defined at the level of the Census block and are compared to the following larger areas: block groups, tracts, counties and Core-Based Statistical Areas (CBSAs), which are an approximation of metropolitan areas.
The calculation of Theil’s H is based on the methodology presented in the report, “The Multigroup Entropy Index” by John Iceland (2004). This methodology involves calculating the entropy, a measure of diversity, for each sub-area and larger area and calculating the population-weighted deviation in entropy values across all sub-areas within each larger area.
Geographies for which no data or limited data were provided or for which the population was less than 10 are represented as having “Insufficient Data.”