The actions of different agents sometimes reinforce each other. Examples are network effects and the threshold models used by sociologists as well as Harvey Leibensteins's "bandwagon effects." We model such situations as a game with increasing differences, and show that tipping of equilibria,...

This papers investigates the efficiency of aggregate choice in the long run when the individual decision is driven by both personal experience and imitation. Personal experience is represented by choice sets depending upon previous choices. Imitation is modeled first through popularity weighting...

In this paper I apply stochastic stability to compare local information to global information in terms of welfare. Under global information agents potentially imitate anyone else, while under local information choices are grouped into information sets and agents can observe and hence imitate...

This paper studies informal insurance across networks of individuals. Two characteristics are fundamental to the model developed here: First, informal insurance is a bilateral activity, and rarely involves explicit arrangements across several people. Second, insurance is a social activity, and...

This paper studies bilateral insurance schemes across networks of individuals. While transfers are based on social norms, each individual must have the incentive to abide by those norms, and so we investigate the structure of stable insurance networks, in which self-enforcement constraints are...

This paper presents a model of local network effects in which agents connected by a social network each value the adoption of a product by a heterogeneous subset of other agents in their 'neighborhood', and have incomplete information about the structure and strength of adoption...

Geography and social links shape economic interactions. In industries, schools, and markets, the entire network determines outcomes. This paper analyzes a large class of games and obtains a striking result. Equilibria depend on a single network measure: the lowest eigenvalue. This paper is the...

We survey the literatures on the economic consequences of the structure of social networks. We develop a taxonomy of 'macro' and 'micro' characteristics of social inter-action networks and discuss both the theoretical and empirical findings concerning the role of those characteristics in...

This paper develops a model of noncooperative network formation. Link formation is two-sided. Information flow is two-way. The paper is based on Bala and Goyal (2000) with the following difference in assumption: the value of information decays as it flows through each agent, and the decay is...

We study a coordination problem where agents act sequentially. Agents are embedded in anobservation network that allows them to observe the actions of their neighbors. We find thatcoordination failures do not occur if there exists a sufficiently large clique. Its existence isnecessary and...