When working together, people engage in non-contractual and informal interactions that constitute the sociology of the group. We use behavioral models and a unique survey of medical groups to analyze how group sociology influences physician incentive pay and behavior. We conclude that informal...

Substantial immigrant segregation in the United States, combined with the increase in the share of the U.S. foreign-born population, have led to great interest in the causes and consequences of immigrant concentration, including those related to the functioning of labor markets. This paper...

"We investigate wage effects of deviations from peer group body mass index (BMI) to evaluate the influence of social norms on wages. Our approach allows for disentangling the influence of the social norm from any (anticipated) productivity effects associated with deviations from a clinically...

"This paper considers the semiparametric identification of endogenous and exogenous peer effects based on group size variation. We show that Lee (2006)'s linear-in-means model is generically identified, even when all members of the group are not observed. While unnecessary in general,...

We provide the first empirical application of a new approach proposed by Lee (2007) to estimate peer effects in a linear-in-means model. This approach allows to control for group-level unobservables and to solve the reflection problem. We investigate peer effects in student achievement in...

This paper is the first to use a randomized trial in the US to analyze the short- and long-term impacts of an after-school program that offered disadvantaged high-school youth: mentoring, educational services, and financial rewards to attend program activities, complete high-school and enroll in...

I consider the alcohol consumption of opposite-gender peers as explanatory to adolescent sexual intercourse and demonstrate that female sexual activity is higher where there is higher alcohol consumption among male peers. This relationship is robust to school fixed effects, cannot be explained...

Hooliganism is on the rise and different countries use different strategies to combat it. We introduce a model where hooligans reap utility from violence and social identity and study the effects of different police strategies. We find that an increase in discriminative policing, provided by...

We study the social interaction of non-smokers and smokers as a sequential game, incorporating insights from social psychology and experimental economics into an economic model. Social norms affect human behavior such that non-smokers do not ask smokers to stop smoking and stay with them, even...

We examine the empirical determinants of student achievement in higher education, focusing our attention on its small-group teaching component (classes or seminars) and on the role of attendance, number of students per class, peers, and tutors. The empirical analysis is based on longitudinal...