A donation may have ambiguous costs or ambiguous benefits. Behavior in a laboratory experiment suggests that individuals use this ambiguity strategically as a moral wiggle room to act less generously without feeling guilty. Such excuse-driven behavior is more pronounced when the costs of a...

Theory commonly posits agents who care both for the level of provision of a public good and the extent to which they personally contribute to the cause. Simply put, agents feel some "warm glow" from the donations they make. I discuss a fundraiser devised to exogenously vary the incentive to give...

We estimate the effect of an increase in time cost on the return behavior of blood donors. Using data from the Australia Red Cross Blood Service, we ask what happens when pro-social behavior becomes more costly. Exploiting a natural variation in which donor wait times are random, we use the...

Volunteer supply is widespread, yet without a price inefficiencies occur due to suppliers' inability to coordinate with each other and with demand. For these contexts, we propose a market clearinghouse mechanism that improves efficiency if supply is altruistically provided. The mechanism, a...