中文摘要
我们研究大学招生中平权行动的后果。我们构建了一个实证框架, 将政策对边际受益学生和被挤出学生的效应与政策的总体效应区分开来。总体效应包括均衡再配置: 受益学生让出的席位由他人填补, 而被挤出的学生转到别处占据席位, 进而又挤出其他学生。我们将该框架应用于巴西的一项大规模政策, 该政策要求所有联邦院校将一半的席位保留给种族和社会经济处境不利的申请者。利用录取分数线, 我们发现边际受益的政策目标学生会就读并毕业于质量更高的专业。其毕业收益约为边际被挤出的非目标学生所受损失的两倍, 这反映出政策目标学生的外部选择更弱。为评估总体效应, 我们估计了一个学位选择与潜在结果模型。在所有被再配置的学生中, 受益学生的收益仍接近被挤出学生损失的两倍, 但均衡再配置使得该政策挤出的学生数量比其惠及的学生数量多约 30%。因此, 非目标学生的损失抵消了政策目标学生毕业收益的约三分之二, 最终全体学生仅获得温和的净收益。
Abstract
We study the consequences of affirmative action in college admissions. We develop an empirical framework that distinguishes the effects on marginally benefited and displaced students from the overall effects of the policy. The overall effects include equilibrium reallocations as benefited students leave seats that others fill and displaced students take seats elsewhere, displacing others in turn. We apply this framework to a large-scale policy in Brazil that required all federal institutions to reserve half their seats for racially and socioeconomically disadvantaged applicants. Exploiting admissions cutoffs, we find that marginally benefited targeted students attend and graduate from higher-quality programs. Their graduation gains are about twice the losses of marginally displaced non-targeted students, reflecting targeted students’ weaker outside options. To evaluate the overall effects, we estimate a model of degree choices and potential outcomes. Among all reallocated students, benefited students still gain nearly twice what displaced students lose, but equilibrium reallocations make the policy displace about 30% more students than it benefits. Non-targeted students’ losses therefore offset about two-thirds of targeted students’ graduation gains, leaving a modest net gain across all students.