Instant Runoff Voting (IRV)

In a traditional first-past-the-post election, the winner of the election may receive far less than a majority of the votes. To ensure that the winner of the election has broad support among the voters, some governments hold a second election, called a runoff election, where the winner of the first election has less than a majority of the vote.

Instant runoff voting provides the benefits of runoff voting but with only one election. Each voter ranks the candidates in order of preference. The votes are first distributed to the candidates according to their first choices. If no candidate has a majority of the votes, then the candidate with the fewest number of votes is eliminated and those ballots are transferred to their next choices. This step is repeated until either a candidate has a majority or only two candidates remain.

Instant runoff voting is also known as ranked-choice voting in the United States and as the alternative vote in the United Kingdom and Australia. Historically, instant runoff voting has also been known as majority preferential voting, English preferential voting, the Hare system, the Ware system. Instant runoff voting is currently used in several cities in the United States (Minneaoplis, MN; Berkeley, Oakland, San Francisco, and San Leandro, CA; and Takoma Park, MD), Australia, and Ireland.

OpenSTV allows you to implement instant runoff voting for your own elections. To learn more about how to do this, please use the links above.