There's a lot of research to suggest that achievement is tied to one's own socioeconomic status. On average a low-income child is not going to do as well on average as a middle-class child. If I am a middle-class child doing well and I'm attending a high-poverty school, I'm going to do less well on average.

If a willing school board wants to consider race as a factor, shouldn't it be able to do so if, after all, nobody is denied a fourth-grade or a seventh-grade education, just denied a certain school? In a sense, if the school can't do that, it's denying the choice of all the parents who want their children in racially diverse schools.