goal of maximizing the academic performance of the lowest ability students. Our assignment algorithm uses peer effects … estimates from the observational data. We find a negative and significant treatment effect for the students we intended to help …. We show that within our "optimal" peer groups, students self-selected into bifurcated sub-groups with social dynamics …

-run peer quality improvements within schools, on the same population. While students at schools with higher-achieving peers …

,000 Italian students graduated from high school between 1985 and 2005 and followed through college and in the labor market. We …-Teacher assignment group, shows large variation that we document to be as good as random. We find that male students who attended a high …, male students from high school classes with >90% males ended up with lower probability of graduating altogether, and they …

generated by changes in the classroom gender composition and those generated by changes in the behavior of students. To control … for potentially confounding unobserved characteristics of schools and students that might be correlated with peer gender … results suggest that an increase in the proportion of girls leads to a significant improvement in students' cognitive outcomes …

intensified among high achievers and in schools with more interracial contact, but non-existent among students in predominantly …

. Moreover, students throughout the school test score distribution appear to benefit from higher achieving schoolmates. On the …

Using data on the universe of students who graduated from U.S. medical schools between 1996 and 1998, we examine … are stronger for blacks, that peer groups are formed along racial lines, or that students with relatively low ability … benefit more from their peers than students with relatively high ability. However, we do find some evidence that peer groups …

performance are potentially observable to peers. We design a field experiment allowing us to test whether students are influenced …