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Optimal Altruism in Public Good Provision


We present a model of altruistically-minded—yet rational—players contributing to a public good. A key feature is the tension between altruism and crowding-out effects. We present three main results: (1) More altruistic behaviour often reduces social welfare; (2) It is almost always optimal for a player to act more selfishly than her true preference; (3) A player’s optimal altruistic commitment is often low or zero—even with strongly altruistic preferences. Applications to a range of public good problems, including climate policy, are discussed. Our results highlight that it will generally be difficult to infer social preferences from observed behaviour.

Robert Hahn

Director of Economics - Smith School of Enterprise and the Environment at the University of Oxford

Former Brookings Expert


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