Trends in Quality-Adjusted Skill Premia in the United States, 1960–2000
研究发现1960至2000年间大学扩招降低了毕业生平均质量，使大学溢价下降6个百分点；标准供需框架需大幅调整才能解释质量变化。
This paper presents new evidence that increases in college enrollment lead to a decline in the average quality of college graduates between 1960 and 2000, resulting in a decrease of 6 percentage points in the college premium. A standard demand and supply framework can qualitatively account for the trend in the college and age premia over this period, but substantial quantitative adjustments are needed to account for changes in quality.