It depends on what question you're trying to answer. "How well does the average student do?" vs "If you raise a family there, how well will your children do?"

It depends on what question you're trying to answer. "How well does the average student do?" vs "If you raise a family there, how well will your children do?" For the former question, you don't want to control for racial mixture. For the latter question, you do. Most parents should care more about the latter question than the former.