What happens after enrollment? An analysis of the time path of racial differences in GPA and major choice

At the private university we analyze, the gap between white and black grade point averages falls by half between the students' freshmen and senior year. This outcome could suggest that affirmative action policies are playing a key role to reduce racial differences. However, this convergence masks two effects. First, the variance of grades given falls across time. Hence, shrinkage in the level of the gap may not imply shrinkage in the class rank...