Several Bay Area cities use ranked-choice voting, and new research co-led by a UC Berkeley professor suggests it changes how people vote.

The study, forthcoming in the journal Management Science, was co-written by Rachel Gershon, an associate professor of marketing at UC Berkeley Haas, with Kristen Duke of the University of Toronto and Ivuoma Onyeador of Northwestern University. Berkeley Haas said the authors believe it is the first causal evidence that ranked-choice rules reduce strategic voting.

How the experiments worked

The researchers ran experiments with about 6,500 U.S. adults recruited online. In the first, 725 people imagined voting for a local official. When their favorite candidate looked like a long shot, only 39% backed that candidate under single-choice rules, compared with 78% under ranked-choice rules.

In a simulated 2024 Republican primary, Berkeley Haas reported, Donald Trump's support fell from nearly 62% to 57% when voters could rank. In a simulated 2020 Democratic primary, Pete Buttigieg rose from 14% to 19% and Joe Biden fell from 57% to 52%. In a final incentivized experiment, 76% backed a Black woman candidate described as their best match under single-choice voting, compared with 84% under ranked choice.

"Right now, voters are forced to play a complex guessing game about who is most electable, often feeling like they can't vote for their favorite without wasting their vote," Gershon told The Daily Californian. "Ranked-choice voting removes that strategic guesswork."

Caveats

Berkeley Haas noted that the elections were simulated, not real, and that the shifts in the candidate-based experiments were modest. In the first experiment, about a quarter of participants whose favorite looked like a long shot still ranked someone else first.

The Daily Californian noted that Berkeley voters approved ranked-choice voting in 2004 and first used it in a city election in 2010. Read our explainer on how ranked-choice voting works in Alameda County.

How to vote

Election Day is Tuesday, Nov. 3. Polls and vote centers close at 8 p.m., and mailed ballots must be postmarked by Election Day and arrive within seven days. You can check your registration and ballot status at sos.ca.gov/elections. California lets you register and vote the same day at a vote center.