The Approximation of Efficient Public Good Mechanisms by Simple Voting Schemes

This paper compares the performance of simple voting rules, called referenda, to the performance of interim efficient mechanisms for the provision of a public good. In a referendum, voters simply vote for or against the provision of the public good, and production of the public good depends on whether or not the number of yes votes exceeds a prespecified threshold. Costs are shared equally. We show that in large populations for any interim efficient allocation rule, there exists a corresponding referendum that yields approximately the same total welfare when there are many individuals. Moreover, if there is a common value component to the voters' preferences, then there is a unique approximating referendum.