The effects of school desegregation on mixed-race births

We find a strong positive raw correlation between black exposure to whites in their school district and the prevalence of later mixed-race (black-white) births, consistent with the literature on residential segregation and endogamy. However, that relationship is significantly attenuated by the addition of a few control variables, suggesting that individuals with higher propensities to have mixed-race births are more likely to live in desegregated school districts. We exploit quasi-random variation from court-ordered school desegregation to estimate causal effects of school desegregation on mixed-race childbearing, finding small to moderate effects that are largely statistically insignificant. Because the upward trend across cohorts in mixed-race childbearing was substantial, separating the effects of desegregation plans from secular cohort trends is difficult; results are sensitive to how we specify the cohort trends and to the inclusion of Chicago/Cook County in the sample. The fact that the addition of a few control variables substantially weakens the cross-sectional relationship between lower levels of school segregation and higher rates of mixed-race childbearing suggests that a substantial portion of the observed correlation is likely due to who chooses to live in places with desegregated schools. Researchers should be cautious about interpreting raw correlations between segregation—whether residential or school—and other outcomes as causal. Our results also point to the need to carefully explore specification of cohort effects in quasi-experimental designs for treatments where cumulative exposure is important.