For those, like my co-blogger, who are interested in the issue of labor market discrimination, I again recommend Kevin Lang's new book, Poverty and Discrimination. On p. 314, Lang writes,
if there is discrimination in the labor market, it is concentrated in the lower end of the skill distribution. Black and white male college graduates have similar earnings. It is black high school graduates and, particularly, high school dropouts whose labor market performance is much worse than that of their white equivalents.
...the difference in the cognitive skills that blacks and whites bring to the labor market is an important source of the difference in their earnings. If we want to address the difference in earnings between blacks and whites, we must address the black-white test score gap.