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...

Copyright affects the distribution of creative content. Taking works off copyright promotes their availability, which benefits consumers. But it also allows generic entry to dissipate producer surplus. This paper examines the effect of a copyright on the availability and price of books when...

This paper surveys the literature on group selection. I describe the early contributions and the group selection controversy. I also describe the main approaches to group selection in the recent literature; fixation, assortative group formation, and reproductive externalities. -- Altruism ; spite...

We test how donors respond to new information about a charity's effectiveness. Freedom from Hunger implemented a test of its direct marketing solicitations, varying letters by whether they include a discussion of their program's impact as measured by scientific research. The base script, used...

This paper presents theoretical and empirical analyses of experiments that test competing theories of altruism, including pure altruism (a preference for the well-being of others), warm glow (a good feeling from giving) and impure altruism (a combination of pure altruism and warm glow). These...

Child labor is a widespread phenomenon and therefore is of interest to both researchers and policy makers. Various reasons for the existence of child labor have been proposed with the goal of designing appropriate solutions. While household poverty is viewed as the main reason for child labor,...

Effective altruists wish to do good while optimizing the social performance they deliver. We apply this principle to the labor market. We determine the optimal occupational choice of a socially motivated worker who has two mutually exclusive options: a job with a for-profit firm and a lower-paid...

Child labor is a widespread phenomenon and therefore is of interest to both researchers and policy makers. Various reasons for the existence of child labor have been proposed with the goal of designing appropriate solutions. While household poverty is viewed as the main reason for child labor,...

This paper presents a model and experimental evidence to explain the "volunteering puzzle" where agents prefer volunteering time to donating money when monetary donations are, ceteris paribus, more efficient for providing resources to charity. In the model agents receive heterogeneous utility...