From Steve Sailer comes a quote from a Wolters book saying that Coleman concluded that segregation hurt black students, but not because it resulted in lower spending per black pupil. Rather, it was because it prohibited white teachers from teaching black students. I wonder how big the effect of teacher measurable ability is?

Coleman's dismay was compounded by another correlation that emerged from the data. Both black and white children seemed to do better on tests if their teachers had done well on a standard test of vocabulary. This was especially problematical because black teachers were "on the whole less well prepared, less qualified, with lower verbal skills, than their white counterparts." This led to "the conjecture that [students] would do less well on average under black teachers than under white teachers." If so, "a major source of inequality of educational opportunity for black students was the fact they were being taught by black teachers." Yet this possibility was so heterodox that the Coleman report did not pursue the matter. In 1991 Coleman expressed regret over the decision "not to ask the crucial question." "A dispassionate researcher," he wrote, "would have gone on to ask the question we did not ask." ...

A commenter noted that this was before discipline became such a problem in schools, and that if black children obeyed a black teacher better, the result could be different nowadays.