Strategyproof Sharing of Submodular Costs: Budget Balance Versus Efficiency

TitleStrategyproof Sharing of Submodular Costs: Budget Balance Versus Efficiency
Publication TypeJournal Article
Year of Publication2001
AuthorsMoulin, H., & Shenker S. J.
Published inEconomic Theory
Other Numbers3509

A service is produced for a set of agents. The service is binary, each agent either receives service or not, and the total cost of service is a submodular function of the set receiving service. We investigate strategyproof mechanisms that elicit individual willingness to pay, decide who is served, and then share the cost among them. If such a mechanism is budget balanced (covers cost exactly), it cannot be efficient (serve the surplus maximizing set of users) and vice-versa. We characterize the rich family of budget balanced and group strategyproof mechanisms and find that the mechanism associated with the Shapley value cost sharing formula is characterized by the property that its worst welfare loss is minimal. When we require efficiency rather than budget balance – the more common route in the literature – we find that there is a single Clarke-Groves mechanism that satisfies certain reasonable conditions: we call this the marginal cost pricing mechanism. We compare the size of the marginal cost pricing mechanism's worst budget surplus with the worst welfare loss of the Shapley value mechanism.

Bibliographic Notes

Economic Theory, Vol. 18, Issue 3, pp. 511-533

Abbreviated Authors

H. Moulin and S. Shenker

ICSI Research Group

Networking and Security

ICSI Publication Type

Article in journal or magazine