We combine survey data on friendship networks and individual characteristics with experimental observations from dictator games. Dictator offers are primarily explained by social distance, giving follows a simple inverse distance law. While student demographics play a minor role in explaining...

The focus of this paper is the endogenous formation of peer groups. In our model agents choose peers before making contributions to public projects, and they differ in how much they value one project relative to another. Thus, the group's preference composition affects the type of contributions...

We characterize the structure of the set of core matchings of an assignment game (a two-sided market with transfers). Such a set satisfies a property we call consistency. Consistency of a set of matchings states that, for any matching v, if, for each agent i there exists a matching ? in the set...

We present a nonparametric "revealed-preference test" for gross substitutes in demand for two goods. (JEL D01, D11)