Heterogeneity in returns to schooling: Econometric evidence from Ethiopia
使用工具变量分位数回归方法，研究埃塞俄比亚不同收入水平人群的教育回报率差异，发现教育对低收入者的收入贡献更大。
The paper investigates whether returns to schooling in Ethiopia vary across the wages distribution of individuals. To do so it adopts an instrumental variables quantile regression framework that allows for both endogeneity of schooling resulting from unmeasured ability, and possible heterogeneity in the impact of schooling. The empirical estimates indicate that education contributes more to the earnings of the individuals at a lower end of the income distribution. Under the assumption that the wage and ability distributions are related, this result is consistent with the notion that education and ability are substitutes. Key Words: returns to schooling; quantile regression