Understanding Peer Effects: On the Nature, Estimation, and Channels of Peer Effects
利用随机分班数据，发现大学教育中能力同伴效应平均为正，但低能力学生受高能力同伴的负面影响；通过安慰剂检验排除估计偏差，并基于课程评价揭示机制是学生互动改善而非教师行为或学生努力调整。
This paper provides evidence on ability peer effects in university education. Identification comes\nfrom the random assignment of students to sections. We find that students on average benefit\nfrom better-ability peers. Low-ability students, however, are harmed by high-ability peers. We\nintroduce a placebo analysis that provides a simple test to quantify the estimation bias driven by\nthe mechanisms described in Angrist (2013). In our setting, the bias is small and does not drive\nour results. Analyzing students’ course evaluations suggests that peer effects are driven by\nimproved student interaction rather than adjustments in teachers’ behavior or students’ effort.