This paper studies both theoretically and empirically the determinants of group formation and of the degree of participation when the population is heterogeneous, both in terms of income and race or ethnicity. We are especially interested in whether and how much the degree of heterogeneity in...

Scholars have pointed to ethnic and other social divisions as a leading cause of economic underdevelopment, due in part to their adverse effects on public good provision and collective action. We investigate this issue in post-war Sierra Leone, one of the world's poorest countries. To address...

We estimate the role of benefits and peer effects in technology adoption using data from randomized distribution of menstrual cups in Nepal. Using individual randomization, we estimate causal effects of peer exposure on adoption; using differences in potential returns we estimate effects of...

This paper develops a model of social interactions and endogenous poverty traps. The key idea is captured in a framework in which the likelihood of future social interactions with members of one's group is partly determined by group-specific investments made by individuals. I prove three main...

We develop a Roy model of social interactions in which individuals sort into peer groups based on comparative advantage. Two key results emerge: First, when comparative advantage is the guiding principle of peer group organization, the effect of moving a student into an environment with...

Two heterogeneous agents contribute over time to a joint project, and collectively decide its scope. A larger scope requires greater cumulative effort and delivers higher benefits upon completion. We show that the efficient agent prefers a smaller scope, and preferences are time-inconsistent: as...

We conducted a laboratory experiment to test the comparative statics predictions of a new approach to collective action games based on the method of stability sets. We find robust support for the main theoretical predictions. As we increase the payoff of a successful collective action (accruing...

We study a standard collective action problem in which successful achievement of a group interest requires costly participation by some fraction of its members. How should we model the internal organization of these groups when there is asymmetric information about the preferences of their...

A menu description presents a mechanism to player i in two steps. Step (1) uses the reports of other players to describe i's menu: the set of i's potential outcomes. Step (2) uses i's report to select i's favorite outcome from her menu. Can menu descriptions better expose strategyproofness,...

This paper introduces a simulation algorithm for evaluating the log-likelihood function of a large supermodular binary-action game. Covered examples include (certain types of) peer effect, technology adoption, strategic network formation, and multi-market entry games. More generally, the...