Volunteering plays a prominent role in the charitable provision of goods and services, yet we know relatively little about why people engage in such prosocial acts. The list of possible motivations is long, but recent research has focused on altruism, reputational concerns, and material...

Empirical studies of the principal-agent relationship find that extrinsic incentives work in many instances, linking rewards to performance increases effort, but that they can also backfire, reducing effort. Intrinsic motivation, the internal drive to work to master a skill or to improve one's...

There has been little systematic study of the mechanisms typically used to raise money for charity. One of the most common is the simple raffle in which participants purchase chances to win a prize at a constant price. We conduct a field experiment randomly assigning participants to four raffle...

There is now an extensive literature on "gift exchange" showing that when principals and agents can trade "gifts" (rewards that should not emerge in a competitive equilibrium), exchange becomes more efficient. However, it is not obvious how gift exchange should be organized if the principal's...