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.