The last decades have seen large improvements in digital advertising technology that allowed firms to better target specific consumer tastes. This research studies the relationship among digital advertising, the rise of varieties, and economic welfare. We develop a model of advertising and...

There have been many studies of the volume-outcome relationship. In all of these, the unit of analysis is the hospital or physician. However, this level of analysis is mostly limited to the use of in-hospital mortality rates and is particularly sensitive to selective referral. Moreover, the...

This paper explores the consequences of grouping workers into diverse divisions on the performance of employees using a dataset containing the detailed personnel records of a large U.S. firm from 1989-1994. In particular, I examine the effects of demographic dissimilarity among co-workers,...

We show that lenders join a U.S. commercial credit bureau when information asymmetries between incumbents and entrants create an adverse selection problem that hinders market entry. Lenders also delay joining when information asymmetries protect them from competition in existing markets,...

We unify two approaches towards identifying native welfare effects of immigration, one emphasizing the immigration surplus (Borjas, 1995,1999), the other identifying a welfare loss due to terms-of-trade effects (Davis & Weinstein, 2002). We decompose the native welfare effect of immigration into...