The Swing Voter's Curse in Proportional Representation Systems (Evidence from Multiple Elections)

Abstract

This paper proposes a theoretical framework to assess the presence of the swing voter's curse in proportional representation (PR) systems. Using individual survey data that contains detailed information on coalition expectations and preferences, this framework is then used to estimate its presence in five recent large elections. Swing voters are defined as those who believe that two or more coalitions are equally likely to be formed. A consistent asymmetric pattern emerges: voters who perceive a very close race between two coalitions are more likely to abstain when they cannot express a strict preference for any of the most likely coalitions. This result does not extend to voters who believe one coalition is much more likely to be formed than all other ones. Finally, this paper addresses the role of ambiguity aversion: results show that individuals who have a harder time assessing the probabilities of the different coalitions are more likely to abstain.