BERKELEY, CA: A landmark 2021 report from UC Berkeley's Othering & Belonging Institute which found racial residential segregation in the United States was getting worse by the decade received a major update Wednesday, with new data, mapping features, analyses, and other tools.
The jaw-dropping finding that about 54 percent of metropolitan regions in the United States had become more segregated since 1990 remains unchanged since the report's last update four years ago.
However, this latest revision includes an updated interactive map and sortable tables of the most segregated cities and metro areas with data from the 2023 American Community Survey (ACS).
The interactive map, first released as part of the original project launch in 2021, shows the levels of segregation in hundreds of cities and metropolitan areas across the country, and allows users to toggle between different decades/years to show changes in segregation.
This updated version includes census boundaries for 2020, whereas the previous map was coded to 2010 boundaries. The map also now includes all counties in the US, whereas the previous version only allowed users to view counties outside of metropolitan areas.
But the most significant update to the map has been the addition of four economic segregation measures: income entropy (a diversity measure), neighborhood categorization, income polarization and Dissimilarity Index. This is the first time the interactive map has includes economic layers so users can visualize the relationship between racial and economic segregation.
The updated project also includes two brand new essays which look at the relationship between segregation and diversity, and a comparison of segregation measures.
Whereas the original release only offered static tables showing cities and counties listed by their levels of segregation, this updated project includes an interactive table. The table is sortable, not just by segregation level, but also by segregation measure. It also allows users to toggle the table between the 2020 Census data, and the 2023 ACS data.
A critical update to the project is the inclusion of new measures of segregation. The principle measure used by OBI when calculating segregation is called the Divergence Index. But there are many other measures of segregation, which are detailed in the report's technical appendix (which has also been updated in this 2025 release).
The most important measure of segregation added to this project is known as “Thiel’s H,” or the Multigroup Entropy Index, which is the preferred measure of segregation by many other scholars.
And finally, the updated project includes a list of dozens of scholarly publications which have cited this project.
In the original publication in June 2021, this project had found that 81 percent of United States metropolitan areas had become more segregated between 1990 and 2019, using the most recent available data from the American Community Survey.
However, several months later when the demographic data from the 2020 Census became available, OBI published an initial update showing that the percentage of metropolitan regions which had become more segregated since 1990 was actually only about 54 percent, rather than 81 percent.
The discrepancy between the two results was due to ACS sample size being far more limited than the decennial Census data. Because of the limited sample size of ACS data, this updated report does not attempt to make claims about changes in segregation nationally based on the 2023 data.
Read more about all of this on the project's 2025 update page.
Media Contact
Marc Abizeid
marcabizeid@berkeley.edu
###
