The School Segregation Data Portal provides data on the racial/ethnic and socioeconomic segregation of public schools for U.S. public school districts and metropolitan areas from 1988 to 2016. All segregation calculations are calculated from raw data from the National Center for Education Statistics Common Core of Data.

The SSDP contains three types of measures of segregation. Dissimilarity and Theil’s index measure how evenly students are distributed by race/ethnicity or socioeconomic status. Isolation measures the extent to which students attend school with students of the same race/ethnicity or socioeconomic status.

For more information on the specific measures of segregation in the SSDP and formulas used in calculating these indices, please see the Technical Appendix.