Over the last two decades, the literature on comparative development has moved from country-level to within-country analyses. The questions asked have expanded, as economists have used satellite images of light density at night and other big spatial data to proxy for development at the desired...

This paper makes the case for greater use of randomized experiments "at scale." We review various critiques of experimental program evaluation in developing countries, and discuss how experimenting at scale along three specific dimensions - the size of the sampling frame, the number of units...

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...