A Theory of Momentum in Sequential Voting
41 Pages Posted: 18 May 2006
Date Written: April 2006
This paper develops a rational theory of momentum in elections with sequential voting. We analyze a two-candidate election in which some voters are uncertain about the realization of a state variable that can affect their preferences between the candidates. Voters receive private signals about the state and vote in an exogenously fixed sequence, observing the history of votes at each point. We show that there is a strict equilibrium with Posterior-Based Voting: each voter votes for the candidate she believes to be better at the time of casting her vote, taking into account the information revealed in prior votes. In this equilibrium, herding can occur on a candidate with positive probability, and occurs with probability approaching one in large voting games. Our results help understand and have implications for sequential voting mechanisms such as presidential primaries and roll-call voting.
Keywords: sequential voting, sincere voting, information aggregation, bandwagons, momentum, information cascades, herd behavior
JEL Classification: C7, D72
Suggested Citation: Suggested Citation