Hmmmm, I wonder if a study conducted by the Cato Institute, or the Heritage Foundation, using the same exact data would have reached the same conclusions. It seemed to me as I read the article that even though the study found significant other factors that contributed to the "gap" it discounted those factors and concluded that the data gives conclusive proof of discrimination.
I'm not going to say because I havent seen it. But this group is hard to beat for biased, agenda-driven work. Check out this critique of their famed fantasy, How Schools Shortchange Girls.
http://www.uaf.edu/northern/schools/myth.html