Volunteer Now or Later: The Effects of Effort Time Allocation on Donations

We study the effect of time flexibility on volunteering. Using an online experiment, we tested predictions of a model of inter-temporal volunteering. Consistent with our theoretical predictions, we find that flexibility in choosing when to allocate effort donations increases overall donations despite the added incentive to renege on a promise to donate. Furthermore, compared to monetary donations, donation rates are higher when people donate effort. We provide a framework for understanding these results.