Earnings Effects of Different Components of Schooling; Human Capital Versus Screening
将实际受教育年限分解为有效年、重复年、跳过年等部分，发现这种分类比传统指标更能解释收入差异，并据此检验人力资本理论与筛选假说，结果支持前者。
In this paper, the authors divide actual years of schooling into effective years, repeated years, skipped years, inefficient routing years, and dropout years. Estimation of earnings functions reveals that this topology is statistically superior to the usual concepts of either actual or effective years of schooling. Based on the authors' distinction, they formulate tests that discriminate between the human capital theory and the screening hypothesis. The results give strong support to the human capital theory and refute the screening hypothesis.