Instant Runoff Voting (IRV) is an alternative electoral system for single-winner elections. It moves away from the traditional plurality system, where the candidate with the most votes wins, even if that total is less than half the total votes cast. IRV is designed to ensure the winning candidate has the support of a true majority of voters. The system achieves this by simulating a series of runoff elections in a single voting event, removing the need for voters to return to the polls for a second time.
Defining Instant Runoff Voting
The core concept of Instant Runoff Voting, also known as ranked choice voting, is how the ballot collects information about the voter’s preferences. Instead of selecting a single candidate, voters rank the candidates in their order of preference (first choice, second choice, and so on). This ranking structure provides election officials with comprehensive data about the voter’s entire preference set.
A voter is not required to rank every candidate. They may choose to rank only their first choice or only a few candidates. If a voter only ranks one candidate, their ballot is still valid, but the vote will only count for that single candidate. This system captures backup preferences, ensuring a voter’s choice remains relevant even if their top candidate is not viable.
How the Elimination and Counting Process Works
The tabulation process for Instant Runoff Voting is conducted in rounds, beginning immediately after the initial election. In the first round, election officials count only the first-choice votes. If any candidate secures a majority (more than 50% of the total first-choice votes), that candidate is immediately declared the winner, and the process ends.
If no candidate achieves the majority threshold, the elimination process begins. The candidate who received the fewest first-choice votes is eliminated. The ballots that listed the eliminated candidate as their first choice are then transferred to their next preference.
For example, if a voter’s first choice (Candidate A) is eliminated, that ballot is transferred to their second-ranked choice (Candidate B), provided Candidate B is still an active candidate. This redistribution simulates a runoff election, where supporters of the eliminated candidate choose between the remaining candidates. A new tally is then conducted with the adjusted vote totals.
This process of eliminating the lowest-vote candidate and redistributing their ballots continues in successive rounds. The process is repeated until only two candidates remain, or until one candidate reaches the absolute majority threshold of votes remaining. Ballots on which all ranked candidates have been eliminated are considered “exhausted” and are no longer counted.
Current Uses and Terminology
Instant Runoff Voting is often referred to by the alternative name, Ranked Choice Voting (RCV), particularly in the United States. While the terms are frequently used interchangeably, RCV is the broader category of voting methods that use ranked ballots, with IRV being a specific mechanism for single-winner elections. Other historical names for IRV include the Alternative Vote (AV) and Preferential Voting.
This electoral system is used in various jurisdictions globally and domestically. On a national level, countries like Australia use a form of IRV to elect members of its House of Representatives. In the United States, two states, Maine and Alaska, have adopted IRV for state and federal general elections.
Local and Organizational Use
Over 50 cities and counties across the U.S. utilize IRV for local municipal elections, including San Francisco, California. The system is also used for internal elections within various political parties and on university campuses to select student government representatives.