Understanding the Data

This report looks at pairs of school districts: school systems that directly neighbor each other and the borders that separate them. There are just over 13,000 school districts in America. Each can have several neighbors, and therefore several borders. After excluding districts that are especially sparse or low in enrollment (for which the drawing of boundaries can reflect particular geographic considerations) and making a small number of additional adjustments, we examined 24,658 pairs of adjacent districts and the borders between them. We measured the divides between neighboring districts in two ways.

First, to measure economic segregation between districts, we compared their poverty rates among school-aged children—the United States Census’s estimated percentage of children between the ages of 5 and 17 residing in the district who live below the federal poverty level. We identified the 100 borders that marked the greatest differences in school-aged poverty rates between adjacent districts in 2021 (the most recent year for which national data are available on both student demographics and school district finances).

Second, we looked at the differences in racial composition between neighboring districts by comparing their percentages of enrolled students of color—that is, students identified as a race or ethnicity other than non-Hispanic white in the National Center for Education Statistics’ Common Core of Data. We identified the 100 borders that created the greatest racial segregation between adjacent districts according to this measure in 2021.

In many instances, we provide contextual information about the school systems separated by these borders. Data about school district finances are drawn from the U.S. Census’s Annual Survey of School System Finances for 2021, and information regarding local incomes and home values is taken from the American Community Survey.

More detailed information about the data and methods used in this report can be found in Appendix D.