The expansion of college education in the United States: Is there evidence of declining cohort quality?

This article documents the expansion of college education in the United States and examines to what extent the increase in the number of college graduates may have lead to a decline in the average quality of college graduates. Using the 1940-90 Census, we compare across birth year cohorts with varying levels of college completion. We find some weak evidence that college graduate men from highly educated cohorts earn a relatively smaller wage premium even controlling for the relative supply effect. However, these cohort quality effects account for only a small fraction of the recent fluctuation in the college wage premium.