We randomly assign more than 6,000 students from 150 primary schools in Bangladesh to work on math assignments in one of three settings: individually, in groups with random schoolmates, or in groups with friends. The groups consist of four people and are balanced by average cognitive ability and...

Using unique geo-coded information on the residential address of a representative sample of American adolescents and their friends, we revisit the importance of geographical proximity in shaping education outcomes. Our findings reveal no evidence of residential neighborhood effects. Social...

This paper studies social-tie formation when individuals care about the geographical location of other individuals. In our model, the intensity of social interactions can be chosen at the same time as friends. We characterize the equilibrium in terms of both social interactions and social...