Ranked choice voting explained: How it works and mistakes to avoid

SAN FRANCISCO - Voting is underway for the November 5th election, and some races could be decided by "ranked choice voting," also known as an "instant runoff."

Oakland, Berkeley, San Leandro and San Francisco are some of the places that have adopted ranked choice voting. San Francisco voters decided in 2002 to switch over to that system.

Filling out the ballots, however, can be confusing for some voters.

NEW IN 2024: SAN FRANCISCO HAS EXPANDED THE RANKING OPTIONS: 
In San Francisco's mayoral race, there are 13 candidates. New this year, voters can rank up to ten choices, instead of just three.

"This system can accommodate up to 10 candidates, so this is the first time I think we've had as many as 10 candidates on a ranked choice contest that are listed on the ballot," John Arntz, San Francisco's Director of Elections said.

HOW DOES RANKED CHOICE VOTING WORK? 
Like traditional elections, the fundamental idea is the same. A candidate must get a majority of votes, which means 50%+1 to win.

The difference kicks in if no candidate wins a majority.

With traditional elections, there would be a runoff between the top two candidates.

With the ranked choice or instant runoff system, voters can rank their alternate choices, indicating who they would vote for in a runoff if their first choice is eliminated.

"They can rank nothing. They can vote one. They can rank up to ten, so it's really up to the voters," Arntz said.

Candidates with the least votes are eliminated in each round.

Voters who ranked those candidates first or highest, get to have their alternate choices counted, until a winner reaches the 50%+1 majority.

"It's a majority of remaining votes in the contest," Arntz said.

WHY ARE SOME CANDIDATES JOINING FORCES, ASKING SUPPORTERS TO RANK OR OMIT OTHER CANDIDATES?
Some candidates are joining forces to say "vote for me first" and "vote for them second or third, etc."  Some are saying to omit candidates that voter does not want to see elected.  

That is a move similar to traditional elections, where candidates who do not make a second round runoff often endorse other candidates.

Leaving a candidate's name blank in the ranked choice voting, means you do not want to give that person your vote in any of the runoff rounds.

In past elections, voters' decisions about whom to rank second, third, etc. have made a difference in the outcome.

In Oakland, the 2010 mayoral race was the first time the city used ranked choice voting. Don Perata had the most first-choice votes (33.73%) compared to Jean Quan (24.47%). In the subsequent rounds, however, more people had ranked Quan as one of their alternate choices. Quan won in the final round with 53,897 votes (50.96%) compared to 51,872 votes for Perata (49.04%). 

In Oakland's 2022 mayoral race, Loren Taylor had the most first-choice votes (33.07%) compared to Sheng Thao (31.79%). More people selected Thao as their alternate choice, however, making Thao the winner in the final runoff round with 57,206 votes (50.3%) compared to Taylor who had 56,529 votes (49.7%). 

RANKED CHOICE VOTING PRACTICE TOOL: 
San Francisco's election website has a ranked choice voting practice tool which voters can use to understand how to fill out their ballots. The tool is in four languages: English, Spanish, Chinese, and Filipino. 

COMMON MISTAKES TO AVOID: 

One common mistake that voters make, is putting all their choices in one column.

"Just make sure you are lining up your marks on the ballot in separate columns," Arntz said.

Also, if a voter puts their first choice candidate in all the ranking spots, their vote will only count once for their first choice. If their candidate is eliminated in the runoff rounds, then that voter will not have any alternate choices listed to be included in the final tally. 

WHAT TO DO IF YOU MAKE A MISTAKE? 

If you make a mistake, election officials say you can always ask for a new ballot, or as a last resort, you can write your intention clearly on the ballot itself, so election officials can understand how your vote should be counted when they do a hand review of the ballot.

Jana Katsuyama is a reporter for KTVU. Email Jana at jana.katsuyama@fox.com. Call her at 510-326-5529. Or follow her on Twitter @JanaKTVU and read her other reports on her bio page.