The Swing Voter's Curse

Abstract

We analyze two-candidate elections in which some voters are uncertain about the realization of a state variable that affects the utility of all voters.. We demonstrate the existence of a swing voter's curse: less informed indifferent voters strictly prefer to abstain rather than vote for either candidate even when voting is costless. The swing voter's curse leads to the equilibrium result that a substantial fraction of the electorate will abstain even though all abstainers strictly prefer voting for one candidate over voting for another. In the 1994 State of Illinois elections there were 6,119,001 registered voters. Among those registered to vote only 3,106,566 voted in the gubernatorial race and only 2,144,200 voted on a proposed amendment to the state constitution. 1 There is nothing exceptional about the level of participation in the 1994 Illinois elections. As in most large elections in the United States, a substantial fraction of the registered electorate abstained from voting at all and of those who did vote a substantial fraction rolled off, i.e., did not vote on every item listed on the ballot. 2 While abstention and roll-off are ubiquitous features of elections together they pose a challenge to positive political theory. One obvious explanation of abstention is costs to vote.