This paper compares two methods to encourage socially optimal provision of a public good. We compare the efficacy of vigilante justice, as represented by peer-to-peer punishment, to delegated policing, as represented by the "hired gun" mechanism, to deter free riding and improve group welfare....

A popular fundraising tool is donation matching, where every dollar is matched by a third party. But field experiments find that matching does not always increase donations. This may occur because individuals believe that peer donors will exhaust the matching funds, so their donation is not...