The Instant-Runoff Voting system allows voters to rank candidates in order of preference to solve the problem of spoiler candidates. Each candidate with the least votes is eliminated, and their voters' votes assigned to those voters' next ranked candidate, until a single candidate has the majority. This allows voters to vote for their ideal candidate without worrying about splitting votes against a candidate they would prefer not to elect. In effect, it simulates multiple elections in one go, hence the name instant-runoff.

While Instant-Runoff Voting reduces the ways in which the voting system can distort the will of the voters, it is not perfect and can still end up electing candidates who would have lost going head to head with another candidate. Instant-Runoff Voting is also extremely uncommon in practice, with only a small number of countries using the system for national elections.

Quick Notes

• As less popular candidates are eliminated, the first candidate to gain a majority of support wins an Instant-Runoff Voting election.

• Under the Instant-Runoff Voting system, voters rank candidates in order of preference on their ballot.