I'm not sure how to reconcile the PA study above with this data about how the achievement gaps are increasingly driven by class rather than race:

Today, despite some setbacks along the way, racial disparities in education have narrowed significantly. By 2012, the test-score deficit of black 9-, 13- and 17-year-olds in reading and math had been reduced as much as 50 percent compared with what it was 30 to 40 years before.

…For all the progress in improving educational outcomes among African-American children, the achievement gaps between more affluent and less privileged children is wider than ever, notes Sean Reardon of the Center for Education Policy Analysis at Stanford. Racial disparities are still a stain on American society, but they are no longer the main divider. Today the biggest threat to the American dream is class.