The Marginal Voter's Curse

The swing voter’s curse is useful for explaining patterns of voter participation, but arises because voters restrict attention to the rare event of a pivotal vote. Recent empirical evidence suggests that electoral margins influence policy outcomes, even away from the 50% threshold. If so, voters should also pay attention to the marginal impact of a vote. Adopting this assumption, we find that a marginal voter’s curse gives voters a new reason to abstain: to avoid diluting the pool of information. The two curses have similar origins and exhibit similar patterns, but the marginal voter’s curse is both stronger and more robust. In fact, the swing voter’s curse turns out to be on a knife edge: in large elections, a model with both pivotal and marginal considerations and a model with marginal considerations alone generate identical equilibrium behaviour.