Most work on social interactions studies a single, composite effect of interactions within a group. Yet in the case of sexual initiation, there are two distinct social mechanisms—peer-group norms and partner availability—with separate effects and different potential interventions. Here I...

This paper provides a framework for identifying preferences in a large network where links are pairwise stable. Network formation models present difficulties for identi fication, especially when links can be interdependent: e.g., when indirect connections matter. We show how one can use the...

We study physician agency and optimal payment policy in the context of an expensive medication used in dialysis care. Using Medicare claims data we estimate a structural model of treatment decisions, in which physicians differ in their altruism and marginal costs, and this heterogeneity is...