Split-ticket voting: an implicit incentive approach

Voters often split tickets, voting for candidates from different parties in simultaneous elections. In this paper, I apply a political agency framework with implicit incentives to study ticket splitting in simultaneous municipal and regional elections. I show that ticket splitting is a natural outcome of the optimal reelection scheme adopted by voters to motivate politicians' efforts in a retrospective voting environment. I assume that an office-motivated politician (mayor or governor) prefers her counterpart to be affiliated with the same political party. This correlation of incentives leads the voters to adopt a joint performance evaluation rule, which is conditioned on the politicians belonging to the same party or different parties. The model is dynamic, generating predictions of split-ticket voting over time. I show that ticket splitting is less likely than electing candidates from the same party, but somewhat depends on ticket splitting in the previous period. Ticket splitting is also more likely in smaller municipalities, where the party affiliation of a mayor is assumed to be of less importance to the governor. These theoretical results are consistent with empirical evidence from simultaneous municipal and regional elections held in Spain.