In a social network, agents have their own reference group that may influence their behavior. In turn, the agents' attributes and their behavior affect the formation and the structure of the social network. We survey the econometric literature on both aspects of social networks and discuss the...

This study explores the formation of buyer-seller relationships in markets with observable quality. We develop a model that explains why relationships form in equilibrium within such markets. A key feature of our model is that as individuals gain experience in the marketplace, they resolve...

Homophily, the tendency of linked agents to have similar characteristics, is an important feature of social networks. We present a new model of network formation that allows the linking process to depend on individuals types and study the impact of such a bias on the network structure. Our main...

This paper studies the dynamics of fundamental research. We develop a simple model where researchers allocate their effort between improving existing fields and inventing new ones. A key assumption is that scientists derive utility from recognition from other scientists. We show that the economy...

We provide new results regarding the identification of peer effects. We consider an extended version of the linear-in-means model where each individual has his own specific reference group. Interactions are thus structured through a social network. We assume that correlated unobservables are...

We introduce uncertainty and risk aversion to the study of international environmental agreements. We consider a simple model with identical agents and linear payoffs. We show that a stable treaty with positive action always exists. While uncertainty lowers the action of signatories, we find...

This paper brings a general network analysis to a wide class of economic games. A network, or interaction matrix, tells who directly interacts with whom. A major challenge is determining how network structure shapes overall outcomes. We have a striking result. Equilibrium conditions depend on a...

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 unobservable and to solve the reflection problem. We investigate peer effects in student achievement in...

This paper considers the formation of risk-sharing networks. Following empirical findings, we build a model where risk-sharing takes place between pairs of individuals. We ask what structures emerge when pairs can agree to form links, but people cannot coordinate links across a population. We...

Favoritism is the act of offering jobs, contracts and resources to members of one's social group in preference to outsiders. Favoritism is widely practiced and this motivates an exploration of its origins and economic consequences. Our main finding is that individuals have an interest to trade...