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...

What do lobbyists do? Some believe that lobbyists' main role is to provide issue-specific information and expertise to congressmen to help guide the law-making process. Others believe that lobbyists mainly provide the firms and other special interests they represent with access to politicians in...

This paper estimates social effects of incentivizing people in teams. In two field experiments featuring exogenous team formation and opportunities for repeated social interactions, we find large team effects that operate through social channels. The team compensation system induced agents to...

This paper estimates treatment size and status specific peer effects that are not detected by widely-used approaches to the estimation of spillovers. In a field experiment using university students, we find that subjects who have been incentivized to exercise increase gym usage more if they have...

This study investigates the role of social networks in aligning the incentives of economic agents in settings with incomplete contracts. We study the New York City taxi industry where taxis are often leased and lessee-drivers have worse driving outcomes than owner-drivers as a result of a moral...

In this paper we estimate the causal effects on child mortality from moving into less distressed neighborhood environments. We match mortality data to information on every child in public housing that applied for a housing voucher in Chicago in 1997 (N=11,848). Families were randomly assigned to...

This paper develops a dynamic model of neighborhood choice along with a computationally light multi-step estimator. The proposed empirical framework captures observed and unobserved preference heterogeneity across households and locations in a flexible way. The model is estimated using a newly...

We study a general class of models with social interactions that might display multiple equilibria. We propose an estimation procedure for these models and evaluate its efficiency and computational feasibility relative to different approaches taken to the curse of dimensionality implied by the...

We study social interactions in the risky behavior of best-friend pairs in the National Longitudinal Study of Adolescent Health (Add Health). Focusing on friends who had not yet initiated a particular behavior (sex, smoking, marijuana use, truancy) by the first wave of the survey, we estimate...