Candidate incentive distributions: How voting methods shape electoral incentives

Abstract

We evaluate the tendency for different voting methods to promote political compromise and reduce tensions in a society by using computer simulations to determine which voters candidates are incentivized to appeal to. We find that Instant Runoff Voting incentivizes candidates to appeal to a wider range of voters than Plurality Voting, but that it leaves candidates far more strongly incentivized to appeal to their base than to voters in opposing factions. In contrast, we find that Condorcet methods and STAR (Score Then Automatic Runoff) Voting provide the most balanced incentives; these differences between voting methods become more pronounced with more candidates in the race and less pronounced in the presence of strategic voting. We find that the incentives provided by Single Transferable Vote to appeal to opposing voters are negligible, but that a tweak to the tabulation algorithm makes them substantial.