Ranked-Choice Voting in San Francisco: Rules and Application

San Francisco uses a ranked-choice voting (RCV) system for most municipal elections, a method that determines winners through successive rounds of vote counting rather than a single-round plurality. This page covers the definition and legal scope of RCV in San Francisco, the mechanics of how ballots are counted, the scenarios that most commonly shape outcomes, and the boundaries where RCV applies — and where it does not. Understanding these rules is foundational to understanding how elected offices are filled across the city's 11 supervisorial districts and beyond.

Definition and Scope

Ranked-choice voting is an electoral method in which voters rank candidates in order of preference — first choice, second choice, third choice — rather than selecting a single candidate. San Francisco adopted RCV by ballot measure in 2002 (San Francisco Department of Elections) and applied it to local races beginning with the November 2004 election. The legal basis is embedded in the San Francisco City Charter, which authorizes the use of preferential voting for city and county offices.

The system applies to the following San Francisco offices:

Mayor
Sheriff
District Attorney
City Attorney
Treasurer
Assessor-Recorder
Public Defender
Board of Supervisors (all 11 districts)
Board of Education
Community College Board

RCV does not apply to state offices appearing on San Francisco ballots — such as State Assembly, State Senate, or statewide constitutional offices — nor does it govern federal races including Congressional seats. Those races remain subject to California state law, which uses a top-two primary system for most partisan offices (California Elections Code, Division 14).

The San Francisco Department of Elections administers ballot design, tabulation software, and public disclosure of round-by-round results. The department is required under the Charter to make complete cast-vote records publicly available after each election.

How It Works

Each voter receives a ballot listing all qualified candidates. The ballot allows ranking up to 3 candidates in order of preference, a limit set by the San Francisco Department of Elections based on ballot card design constraints. Voters may rank fewer than 3 candidates; they are not penalized for doing so, but a ballot that ranks only one candidate will be exhausted if that candidate is eliminated.

Counting proceeds in rounds:

First count: All first-choice rankings are tallied. If any candidate receives more than 50 percent of the valid first-choice votes, that candidate wins outright and no further rounds occur.
Elimination: If no candidate crosses the 50 percent threshold, the candidate with the fewest first-choice votes is eliminated.
Vote transfer: Ballots that listed the eliminated candidate as their first choice are redistributed to whichever remaining candidate those voters ranked next.
Repeat: The process repeats, round by round, until one candidate holds more than 50 percent of the active (non-exhausted) ballots.

A ballot becomes "exhausted" when all the candidates ranked on it have been eliminated. Exhausted ballots are removed from the active pool; the 50 percent threshold is calculated against remaining active ballots, not the total ballots cast. This distinction is governed by San Francisco's Charter provisions and has been a point of academic scrutiny in election administration literature.

The San Francisco Board of Supervisors races are among the most frequently contested under this format, given the 11-district structure and the frequency of crowded candidate fields.

Common Scenarios

Scenario 1 — First-round majority: In races with a dominant frontrunner, a candidate may secure over 50 percent of first-choice votes in the opening count. RCV collapses into a single-round result, and the multi-round process does not engage.

Scenario 2 — Crowded field, multiple rounds: Supervisorial races frequently feature 5 to 12 candidates. In these contests, the elimination process can require 8 or more rounds before a candidate clears 50 percent of active ballots. The November 2010 District 10 race required more than 20 rounds of elimination, a case frequently cited by the San Francisco Department of Elections as illustrative of RCV's capacity to resolve competitive multi-candidate contests (SFUSD/SF Elections historical results).

Scenario 3 — Ballot exhaustion effect: When voters rank only 1 or 2 candidates and all those candidates are eliminated early, their ballots become exhausted. In highly fragmented races, exhaustion can meaningfully reduce the active ballot pool. The winner may ultimately hold a majority of active ballots while representing a smaller share of total ballots originally cast. This structural dynamic differentiates RCV from a traditional runoff, where all voters are invited to participate in a second election regardless of how they voted in the first.

RCV versus Traditional Runoff: Under the pre-2004 system, San Francisco held separate runoff elections between the top two vote-getters when no candidate won a first-round majority. RCV consolidates this into a single election day, eliminating the cost of a standalone runoff and historically reducing the turnout drop-off that affected separate runoff elections. California's state system, by contrast, uses a top-two primary that advances two candidates to a general election regardless of party affiliation — a structurally different mechanism than either San Francisco's RCV or the old two-round runoff.

Decision Boundaries

RCV outcomes hinge on several critical decision points in administration and candidate strategy:

Ballot position: San Francisco conducts a randomized candidate name-ordering process for each district to prevent consistent position bias across precincts.
The 3-ranking cap: Because San Francisco limits voters to 3 rankings (unlike jurisdictions such as Alaska, which uses a 4-candidate ranked ballot under its 2020 ballot measure), voters in races with more than 3 viable candidates face a strategic choice about which candidates to include.
Tie-breaking: In the event of a tie between candidates at the elimination threshold, San Francisco election rules specify a random tie-breaking procedure administered publicly under observation.
Certification timeline: Round-by-round tabulation occurs after the close of voting and continues as mail and provisional ballots are processed. Final certified results may differ from election-night preliminary tallies; the Department of Elections posts updated round-by-round reports as counting proceeds.

Contested RCV elections in San Francisco are subject to challenge through the San Francisco Superior Court, which has jurisdiction over local election disputes. State-level appeals proceed through the California Court of Appeal.

For context on how municipal elections are structured more broadly — including primary dates, candidate qualification thresholds, and the relationship between district and citywide races — the San Francisco Municipal Elections reference provides the governing framework. The San Francisco ranked-choice voting reference page covers administrative detail specific to ballot design and tabulation vendor contracts.

For a broader orientation to how San Francisco's local government bodies interact with electoral outcomes, the site index provides an organized entry point to civic and governmental topics covering the full scope of city and county operations.

Scope and Coverage Limitations

This page covers RCV as it applies within the City and County of San Francisco. The scope does not extend to the following:

Alameda, Marin, or other Bay Area counties, which operate under separate county election codes (Alameda County also uses RCV for some races under California Elections Code authority, but under distinct local rules)
California statewide or federal offices appearing on San Francisco ballots, which are governed by the California Secretary of State and the U.S. Election Assistance Commission respectively
School board or community college board races in neighboring jurisdictions
Special district elections (e.g., BART board, SFMTA board) that are not directly governed by the San Francisco City Charter's RCV provisions

Questions about how RCV interacts with the city's redistricting cycle — which reshapes supervisorial district boundaries following each decennial Census — fall under San Francisco Redistricting coverage.