This paper considers a dynamic model of the evolution of open source software projects, focusing on the evolution of quality, contributing programmers, and users who contribute customer support to other users. Programmers who have used open source software are motivated by reciprocal altruism to...

Transplants of donated stem cells save the lives of many patients with blood diseases. Donation is somewhat painful, but rarely has lasting adverse effects. Patients can accept transplants only from donors with compatible immune systems. Those lacking a sibling match must seek donations from the...

Transplants of donated stem cells save the lives of many patients with blood diseases. Donation is somewhat painful, but rarely has lasting adverse effects. Patients can accept transplants only from donors with compatible immune systems. Those lacking a sibling match must seek donations from the...

Family businesses make up forty percent of the Fortune 500 companies in the US, generate about two-thirds of the German GDP, employ about one-half of the labor force in Britain, and account for the majority of the private economies in developing countries. This paper develops a theory of family...

Previous work on the effects of private income transfers has been confined to intra-family interactions. One implication of this work is that such transfers benefit recipients by insuring against labor market risks. Allowing for equilibrium labor market responses, however, one would expect the...

Previous work on the effects of private income transfers has been confined to intra-family interactions. One implication of this work is that such transfers benefit recipients by insuring against labor market risks. Allowing for equilibrium labor market responses, however, one would expect the...

There are currently debates both about the ability to measure the value of moral sentiments and the nature of benefit-cost analysis. Moral sentiments can be reasonably measured in many situations and their consideration can improve benefit-cost analysis in any case. This argument is presented by...

We study a credence goods problem - that is, a moral hazard problem with non-contractible outcome - where altruistic experts (the agents) care both about their income and the utility of consumers (the principals). Experts' preferences over income and their consumers' utility are convex, such...

We analyze the offering, asking, and granting of help or other benefits as a three-stage game with bilateral private information between a person in need of help and a potential help-giver. Asking entails the risk of rejection, which can be painful: since unawareness of the need can no longer be...