As election day approaches, San Francisco voters are set to once again utilize the ranked-choice voting (RCV) system that has been in place for the past 20 years to select their city leaders. This voting method allows voters to rank their preferences for multiple candidates rather than choosing just one, aiming to enhance voter choice and reduce the prevalence of tactical voting seen in traditional elections.

Since 2004, San Francisco has employed this preferential voting system for electing the mayor, city council members, and other local officials. Unlike the single-round voting or primary-plus-runoff systems common in many other U.S. cities, this approach enables San Francisco voters to express their support for several candidates in a single election.

Elections officials explain that in San Francisco’s ranked-choice voting system, voters can not only cast a ballot for their most preferred candidate but also rank up to three candidates in order of preference. For instance, in the upcoming mayoral election, voters might choose to give their first choice to their top candidate, then select their second and third favorites. If a candidate receives more than 50% of the votes in the initial round, they are declared the winner.

However, if no candidate achieves a majority in the first round, the counting process moves to the next stage. Candidates with the fewest votes are eliminated, and their ballots are redistributed to voters’ next preferred candidates. This process continues in rounds until one candidate ultimately secures more than 50% of the votes.

This system is designed to ensure that the winning candidate has broad support from the electorate, even if they do not receive the most votes in the first round. Ranked-choice voting allows voters to express their preferences for multiple candidates, helping to avoid the dilution of votes that can occur when many candidates are on the ballot.

Moreover, it mitigates the problem of tactical voting that often occurs in traditional elections, where voters may feel compelled to support a less preferred candidate to avoid “wasting” their vote.

Taking this year’s mayoral election as an example, San Francisco’s contests typically attract multiple candidates, and each contender aims to become a voter’s “second choice” or “third choice,” which is crucial under the ranked-choice system. Throughout the campaign, candidates must appeal broadly to various voter demographics, rather than solely relying on their core supporters.

In the 2018 mayoral election, for example, candidate London Breed led in the initial round but failed to achieve an outright majority. As the rounds progressed and other candidates were eliminated, Breed gradually garnered second and third-choice votes from other candidates’ supporters, ultimately winning the election and becoming mayor.