In an excellent Education Next blog post, Dr. Brian Kisida and Olivia Piontek respond to claims by UCLA’s Civil Rights Project and others that school segregation has worsened.  The authors offer a useful summary of the difficulties of measuring it using absolute and relative measures. They observe,

In contrast, relative measures of segregation take into account the underlying composition of students, making them more comparable across locations and over time. They are also conceptually different in that they measure how evenly a given population of students is distributed across an entire school system. This makes intuitive sense, as segregation implies that some students are segregated from other students—relative to some underlying pool of students a school could enroll.

This issue with measuring segregation is well-known in the academic community, and there is ample scholarly evidence using relative measures of segregation that adjust for the underlying composition of students in school systems. Using these more sophisticated relative measures, such as the dissimilarity index and the variance-ratio index, examinations of trends find that segregation has been flat or modestly decreased over the past 20 years. In summary, massive resegregation is not occurring, and students are roughly just as evenly distributed across school systems as they were 20 years ago.

Kisida and Piontek conclude, “This [segregation] is an outrage that demands serious attention and action. But as we devise strategies and search for solutions, it is imperative that we are motivated by a complete picture of the problem we are trying to address.”