Complex sentence: Graduates of the top 14 law schools tend to have higher earnings, on average, than graduates of the bottom 190 law schools, and graduates with higher law school GPAs tend to have higher earnings than students with lower law school GPAs.
Split into simpler sentences: Graduates of the top 14 law schools tend to have higher earnings, on average, than graduates of the other 190 law schools. In addition, graduates with higher law school GPAs tend to have higher earnings than students with lower law school GPAs.