This paper describes a range of methods which have been proposed to study interactions in economic and social contexts. By interactions, we refer to interdependences between individual decisions which are not mediated by markets. These types of models have been employed to understand phenomena...

This paper uses a unique data set to measure peer effects among college age roommates. Freshman year roommates and dormmates are randomly assigned at Dartmouth College. I find that in this group, peer effects are very important in determining levels of academic effort and in decisions to join...

A common practice in the fields of education, mental health, and juvenile justice is to segregate problem youths in groups with deviant peers. Assignments of this sort, which concentrate deviant youths, may facilitate deviant peer influence and lead to perverse outcomes. This possibility adds to...

This paper develops a theory of promotion based on evaluations by the already promoted. The already promoted show some favoritism toward candidates for promotion with similar beliefs, just as beetles are more prone to eat the eggs of other species. With such egg-eating bias, false beliefs may...

How important is human capital at the top of the U.S. income distribution? A primary source of top income is private "pass-through" business profit, which can include entrepreneurial labor income for tax reasons. This paper asks whether top pass-through profit mostly reflects human capital,...

This chapter reviews the recent debate about the role of social capital in economics. We argue that all the difficulties this concept has encountered in economics are due to a vague and excessively broad definition. For this reason, we restrict social capital to the set of values and beliefs...

We develop a model in which the capital of the intermediary sector plays a critical role in determining asset prices. The model is cast within a dynamic general equilibrium economy, and the role for intermediation is derived endogenously based on optimal contracting considerations. Low...

While the economies of the fifteen countries that were in the European Union (EU15) in 2000 will continue to grow from now until 2040, they will not be able to match the surges in growth that will occur in South and East Asia. In 2040, the Chinese economy will reach $123 trillion, or nearly...