-achieving students and no significant effects among low achievers. Students in top tracking enjoyed multiple advantages, particularly a … concentration of high-performing peers and a very homogeneous classroom, that facilitated the teacher's work and increased students …' effort l evels. Bimodal classes fostered greater effort levels among top students, while teachers induced less competition …

of a two-day freshman orientation program for university students, I find that higher ability peers generate positive … students by 0.05 to 0.08 SD. I provide evidence that the effects result from the formation of lasting social ties, and that …

unobserved. For instance, in education, academic effort is often proxied by GPA. We propose an alternative approach that … from classical estimates (where effort is approximated) if the network includes isolated students. Applying our approach to … data on high school students in the United States, we find that peer effect estimates relying on GPA as a proxy for effort …