We develop a theoretical framework to study illicit drugs markets and we estimate it using data on purchases of crack cocaine. Buyers are searching for high-quality drugs, but they determine drugs' quality (i.e., their purity) only after consuming them. Hence, sellers can rip off first-time...

We study the effects of improvements in eBay's rating mechanism on seller exit and continuing sellers' behavior. Following a large sample of sellers over time, we exploit the fact that the rating mechanism was changed to reduce strategic bias in buyer rating. That improvement did not lead to...

The Paper analyses a standard Downsian model of election with two opportunistic parties. We assume that, after choosing their ideological position but before the election takes place, parties can affect the quality of their platforms by exerting some unobservable effort. When voters either...

We propose a basic theoretical model of eBay’s reputation mechanism, derive a series of implications and empirically test their validity. Our theoretical model features both adverse selection and moral hazard. We show that when a seller receives a negative rating for the first time his...

In the 'Knightian' theory of entrepreneurship, entrepreneurs provide insurance to workers by paying fixed wages and bear all the risk of production. This paper endogenizes entrepreneurial risk by allowing for optimal insurance contracts as well as the occupational self-selection. Moral hazard...

This paper analyzes the impact of labor market competition and skill-biased technical change on the structure of compensation. The model combines multitasking and screening, embedded into a Hotelling-like framework. Competition for the most talented workers leads to an escalating reliance on...

This paper discusses the optimal organization of sequential agency problems with contractible control actions under limited liability. In each of two stages, a risk-neutral agent can choose an unobservable effort level. A success in the first stage makes effort in the second stage more...