VOTING-BEHAVIOR AND INFORMATION AGGREGATION IN ELECTIONS WITH PRIVATEINFORMATION

We analyze two-candidate elections in which voters are uncertain about the realization of a state variable that affects the utility of all v oters. Each voter has noisy private information about the state variab le. We show that the fraction of voters whose vote depends on their pr ivate information goes to zero as the size of the electorate goes to i nfinity. Nevertheless, elections fully aggregate information in the se nse that the chosen candidate would not change if all private informat ion were common knowledge. Equilibrium voting behavior is to a large e xtent determined by the electoral rule, i.e., if a candidate is requir ed to get at least x percent of the vote in order to win the election, then in equilibrium this candidate gets very close to x percent of th e vote with probability close to one. Finally, if the distribution fro m which preferences are drawn is uncertain, then elections will genera lly not satisfy full information equivalence and the fraction of voter s who take informative action does not converge to zero.