| Ismar Volić | Good Good Good |
We are a team of mathematicians who recently concluded a study aimed at answering this and related questions. We analyzed some 2,000 ranked choice elections from the U.S., Australia, and Scotland. We supplemented those real-world results with 60 million simulated elections.
The results were clear: Ranked choice voting performed much better across all the measures we tested, including spoiler, vote-splitting, strength of candidates and strategic voting.
The evidence is overwhelming
Plurality voting produced a spoiler up to 15 times more often than ranked choice voting. And it was 50% more likely to elect an extreme candidate. Plurality, furthermore, was highly susceptible to vote-splitting, while ranked choice voting was nearly impervious to it.
Ranked choice voting picked strong candidates up to 18 times more frequently than plurality voting, where by “strong” we mean candidates who received many first-place votes and also had broad support, even among their noncore supporters. This method also rarely elects a weak or fringe candidate and typically elects a candidate near the electorate’s ideological center.
The math is in, and the evidence is overwhelming: Plurality voting is broken. Ranked choice voting will not solve every democratic ailment, but it is a good step toward mending them.