We examine friendships and study partnerships among university students over several years. At the aggregate level, connections increase over time, but homophily on gender and ethnicity is relatively constant across time, university residences, and different network layers. At the individual...

We study risky behavior of adolescents. Concentrating on smoking and alcohol use, we structurally estimate a dynamic social interaction model in the context of students' school networks included in the National Longitudinal Study of Adolescent Health (Add Health). The model allows for...

How do information interventions affect individual efforts to expand social networks? We study a randomized controlled trial of a program providing information on settling in the U.S. for new immigrants from the Philippines. Improved information leads new immigrants to acquire fewer new social...

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...

We develop and analyze a tractable empirical model for strategic network formation that can be estimated with data from a single network at a single point in time. We model the network formation as a sequential process where in each period a single randomly selected pair of agents has the...

This paper uses data from global and Canadian surveys data to estimate the powerful linkages between social connections, their related social identities, and subjective well-being. Our explanatory variables include several measures of the extent and frequency of use of social networks, combined...

We develop a model of informal risk-sharing in social networks, where relationships between individuals can be used as social collateral to enforce insurance payments. We characterize incentive compatible risk-sharing arrangements and obtain two results. (1) The degree of informal insurance is...

We specify and implement a test for the presence and importance of labor market network based on residential proximity in determining the establishments at which people work. Using matched employer-employee data at the establishment level, we measure the importance of these network effects for...

To estimate peer effects in college achievement we exploit a unique dataset in which individuals have been exogenously assigned to peer groups of about 30 students with whom they are required to spend the majority of their time interacting. This feature enables us to estimate peer effects that...