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Ranked-choice (or "ordinal") voting is any electoral system in which voters rank or "preference" candidates in order.
Ranked-choice (or "ordinal") voting is any electoral system in which voters rank or "preference" candidates in order.
Intro to Ranked-choice Voting
Intro to Ranked-choice Voting
Ranked-choice Voting (RCV) is a large family of electoral systems that ask voters to rank candidates in order of their preference. There are a wide variety of ranked systems, including Condorcet Voting, Bucklin Voting, and Instant Runoff.
In the United States, RCV usually refers to three ranked voting systems in which vote counting takes place in rounds and votes are transferable, which means that a vote can be transferred from the first to later preferences listed on a voter's ballot.
On this page, we'll first discuss the three variants commonly debated (and currently in use) in the United States, before exploring less well-known RCV systems.
RCV Variants in the U.S.
RCV Variants in the U.S.
Ranked-choice voting (RCV) is a term used in the United States commonly used to describe three RCV variants in use in the US in which:
Voters rank candidates in order of preference;
Votes are transferable and can move from the first to a later preference listed on a voter's ballot; and
Votes are counted in rounds that sequentially elect or eliminate candidates and progressively draw on more information from voters’ ballots.
There are three common RCV variants:
Instant Run-off Voting (IRV)
Single Transferable Vote (STV)
Preferential Block Voting (PBV)
All variants share these features:
Voters rank candidates.
Vote counting proceeds in rounds.
The unique effects of the RCV variant are greater as more voters rank candidates more fully.
They differ in most other respects.
Instant Run-off Voting
Instant Run-off Voting
A majoritarian system for electing a single winner, either at-large or in districts, in which voters get a single vote and rank candidates in order of preference. To win a candidate must receive a majority of "active" votes.*
After voters cast their ballots, votes are tallied. If a candidate wins a majority of first rankings, they win. If no candidate wins a majority of first rankings, a second round of vote counting – an “instant run-off” commences. The candidate with the fewest first rankings is eliminated and ballots with that candidate as their top choice will have their next choice counted. Votes are tallied and the process continues until one candidate has more than half of the remaining vote.
* In the version of IRV used in the United States, in which preferences are optional (i.e. voters MAY rank candidates), many voters' ballots will exhaust over multiple rounds of counting, meaning that the eventual winner may not achieve the true majority standard (of all votes cast) but instead a majority of "active" votes that remain in the count (and have not exhausted). In Australia, this form of IRV is known as "optional preferential voting," in contrast to "full preferential voting," in which voters must rank all candidates to cast a valid ballot."
Preferential Block Voting
Preferential Block Voting
Often called the "Utah Variant," PBV is a plurality system for electing multiple winners, either at-large or in districts, in which voters rank candidates in order of preference. To win, a candidate must receive a majority of the votes in that given round of counting.
When electing the first winner, voters’ first choices are tallied as they would be under IRV until a candidate is elected. To elect the second and subsequent winner, ballots are retallied using the IRV process as if the elected candidate(s) had not run for office, with each ballot counting for the highest ranked candidate that has not been elected.
This process continues until the desired number of candidates have been elected.
Single Transferable Vote
Single Transferable Vote
A pluralistic (often called "semi-proportional") system for electing multiple winners, either at-large or in districts, in which voters get a single vote and rank candidates in order of preference. To win, a candidate must receive a threshold number of votes, which is equal to 1/4th of the total vote in three-winner races, 1/6th in five-winner races, and 1/11th in 10-winner races. There are several different ways to calculate the exact number of votes in this threshold (also known as a “quota”). For more information, see this post from the British Electoral Reform Society.
When electing the first winner, voters’ first choices are tallied. Those candidates who have met the threshold are elected. If fewer candidates have been elected than there are seats to fill, the surplus votes of each elected candidate are transferred to the voters’ next most preferred (not-yet-elected) candidate. If, as a consequence of the transfer process, additional candidates reach the threshold, they are elected and their surplus votes transferred. This process continues until no additional candidates reach the threshold as a consequence of surplus vote transfer.
Once there are no additional surplus votes to transfer, the candidate with the fewest votes is eliminated, and the ballots of voters who voted for the eliminated candidate now count for their next most preferred (not-yet-elected) candidate. If additional candidates reach the threshold as a consequence of this process, they are elected and their surplus votes transferred according to the process above.
This process of electing candidates, transferring surpluses, and eliminating last-placed candidates continues until the desired number of candidates have been elected.
STV produces more proportional results in larger districts (i.e. ones in which more candidates are elected at a time). STV will elect a more proportional 20-member state legislature using two 10-winner districts than it will using 10 two-winner districts.
Making Use of Extra Information
Making Use of Extra Information
Ranked voting asks for more information from voters than more common systems (like List Proportional or First-past-the-post). Instead of the common binary choice (a filled in oval versus an empty oval) in typical American elections, voters are asked to provide a relative ranking of the candidates. In some versions of ranked voting (such as those used in Australian elections), voters must rank ALL the candidates in order to cast a ballot.
What does RCV do with all this extra information?
The three variants of RCV use the extra information they get from voters in different ways.
IRV ignores the vast majority of the information it solicits from voters, relying heavily on voters’ first choices and a small subset of second choices.
When it does introduce additional information, it does so from the bottom up. RCV uses information on the preferences of voters for the least popular candidates as they are eliminated and, in a manner of thinking, saves votes cast for unpopular candidates. Votes flow 'upward' from the least popular toward the more popular candidates.
PBV and STV make more use of the ranking information, but to very different ends: PBV uses the extra information to supporters of popular candidates another go at electing another winner; STV uses ranking information to equalize the efficacy of each voter’s vote and minimizing wasted votes (votes that do not count toward electing a candidate).
PBV is, in effect, a “top-down” method. Like IRV, PBV introduces information on the preferences of voters for the least popular candidates to help elect the most popular candidates. However, as each candidate is elected, the counting resets. The ballots of all voters are reintroduced – including those who cast a first choice for the elected candidate(s). Votes are counted as if the winning candidate(s) was never in the race, so these voters’ votes flow “downward” to contribute to the election of subsequent candidates.
Meanwhile, in pursuit something more proportional, STV goes both ways – introducing information on the preferences of voters for the most popular candidates (at a smaller, weighted value), then the least popular (at full value), then the next most popular (at a smaller, weighted value), then the next least popular (at full value), and so on.
The three variants are summarized below.
What Happens when Voters Don’t Rank?
What Happens when Voters Don’t Rank?
In the U.S. context, voters are rarely required to rank all candidates to cast a valid ballot. (By contrast, in Australia it is standard to mandate voters rank all candidates lest their vote not count at all, a system we call "Full Preferential Voting.")
The extent to which any RCV system has distinctive characteristics depends significantly on (1) how many voters rank candidates and (2) how many candidates they rank.
As more voters rank all candidates, IRV is more likely to elect a candidate with a majority of support. If few voters rank all or most candidates, IRV will almost always behave like single-winner plurality. If few voters rank, IRV becomes susceptible to vote splitting, wasted votes, and the spoiler effect.
The results from STV will be more proportional as more voters rank all or most candidates. If few voters rank candidates, STV will behave a lot like Single Non-transferable Vote (SNTV), a semi-proportional system.
As more voters rank all candidates, PBV is more likely to elect candidates with the most overall support and allow the same plurality of voters to elect all candidates. If few voters rank candidates, PBV will behave more like Single Non-transferable Vote (SNTV), a semi-proportional system.
Counting votes in RCV
Counting votes in RCV
Under IRV, every voter’s first choice is counted. If a candidate receives more than half of the first choices, that candidate wins, just like in any other election. However, if there is no majority winner after counting first choices, the race is decided by an "instant runoff." The candidate with the fewest votes is eliminated, and voters who picked that candidate as ‘number 1’ will have their votes count for their next choice. If the ballot does not contain any additional rankings for candidates still in the race, it will “exhaust” and no longer remain in the count.
This process continues until there is a majority winner or a candidate won with more than half of the votes remaining in the count.
In a typical IRV election, candidates win in the first round with a majority of the vote. Even in contests that continue to second and subsequent rounds of counting, only the first preference of a large majority of voters’ rankings will be tabulated, leaving the remaining rankings unused.
Under PBV, counting looks a lot like IRV, except that it repeats for each winner and makes more use of voters’ rankings.
After the first winner has been elected using the procedure for IRV outlined above, the count for the second winner begins. Essentially all choices for the first winner are ignored, and the count proceeds using IRV but without that winning candidate. Essentially, a whose first choice won now has their second choice bumped up to first and all of the ballots are re-tallied. If a ballot does not contain any additional rankings for candidates still in the race, it will “exhaust” and no longer remain in the count.
The process continues, with each elected candidate being eliminated from the count, until the required number of candidates are elected. Note that, in theory at least, a voter’s vote can elect as many candidates as are up for election.
The counting in STV combines elements of IRV, PBV, and some complex math. In the first round, every voter’s first choice is counted. If any candidates receive more than the threshold percentage of first choices, those candidates win.
The threshold is defined as a percentage of vote equal to 1/(the number of candidates to be elected + 1)%. Using the example above, a candidate in a contest for a three-member city council seat must receive more than 1/(3+1)%, or 25%, of votes cast to win a seat. This means that, in a three-winner race, a candidate must win one fourth of the votes (plus one vote). Typically, more than half of candidates will be elected in the first round, with their election being easy to explain.
But then comes the complexity. (Expand for the complexity.)
Under STV, the next stage is to redistribute the surplus votes of elected candidates. Each candidate needs only the threshold number of votes to win, and so STV, which aims to minimize wasted votes and maximizes the use of the ranking information provided by voters, takes that excess and moves them to the second-choice candidate on each voter’s ballot.
Numerous transfer formulas, including “random subset,” Gregory “fractional transfer value,” and Hare-Clark, have been devised. Almost every STV jurisdiction uses a slightly different one. The transfer formulas vary in whether they transfer a set of randomly selected ballots from the winning candidate’s haul (equal to the number of ballots in excess of the surplus that candidate has) or transfer all ballots as a fraction (so that each vote counts for less than one vote for the winning candidate and the remaining—fractional—value is transferred to the second choice). However, at their core, each transfer formula seeks to produce an outcome that is as proportional as possible to overall voter preferences by making use of the ranking information on voters’ ballots and adhering to the one-vote one-value principle.
Once the surplus votes of each elected candidate are redistributed, election administrators check whether any other candidate has won. If they have, we repeat the process of redistributing their surplus votes until no candidate is newly elected.
Then, like IRV and PBV, the candidate with the fewest votes is eliminated and their preferences distributed to the candidates who are yet to be elected or eliminated according to the preferences listed on the ballot. The process repeats until a candidate is elected. If additional candidates reach the threshold as a consequence of this process, they are elected and their surplus votes transferred according to the process above.
This process of electing candidates, transferring surpluses, and eliminating last-placed candidates repeats until the desired number of candidates have been elected.
The complexity of vote counting under STV, or, rather, the difficulty of succinctly explaining STV vote counting, is one of the system’s chief disadvantages.
Other less common (in the US) variants
Other less common (in the US) variants
Borda Count
Borda Count
Invented by French mathematician Jean-Charles de Borda in 1770, the Borda Count is a majoritarian single-winner form of ranked voting. The Borda Count uses a points system to select the winner. Voters rank candidates in order of preference. For an election featuring N candidates, each candidate receives points from every ballot, N-1 points for each 1st preference, N-2 points for each 2nd preference, and so on down to 0 points for each Nth preference. Once points from all ballots are allocated, the candidate with the most points is declared the winner. See Black (1976) for more information.
Bucklin Method
Bucklin Method
A majoritarian single-winner variant of RCV, Bucklin voting has its origins in the American West during the Progressive Era. Voters rank candidates in order of preference. If no candidate wins a majority of votes, voters' second preferences are taken into consideration with all candidates receiving an additional vote for each second preference they received. This process continues until a winner is found.
Bucklin voting is explicitly majoritarian. James W. Bucklin devised the system as part of his stated plan "to restore majority elections and true representative government" (Bucklin 1911). Bucklin voting spread across the US West for local city elections; several US states including Colorado, Washington, Minnesota and Oklahoma used it in the early 20th century (Richie 2004).
Vote counting proceeds in rounds. In the first round all ballots are distributed amongst the candidates according to first preferences. If no candidate has achieved 50% of the vote, all candidates receive an additional vote for each second preference they received. These second preference votes are added to the initial vote tally and no candidates are eliminated. If any candidate has now received greater than 50% of the vote, that candidate is elected. If two (or more) candidates achieve greater than 50% of the original vote in the same round, the candidate with the largest vote wins. If no candidate has yet received 50% of the vote, all candidates receive a further vote for any third preferences they receive, and so on, until a winner is found.
Condorcet Voting
Condorcet Voting
A majoritarian single-winner form of ranked voting, Condorcet Voting was proposed by Marquis de Condorcet, an 18th century French mathematician. Voters rank candidates in order of preference. During counting, every possible combination of two candidates are compared. Ballots are distributed between the two candidates according to preferences and the candidate with the larger vote tally is declared the winner of that match up. If a candidate exists who wins every pairwise match up, that candidate is the Condorcet winner and is elected. The only known instance of Condorcet Voting being employed in an election for public office was for city elections in Marquette, Michigan in the 1920s (Hoag and Hallett 1926).
Coombs' Method
Coombs' Method
A pluralistic single-winner variant of ranked voting proposed by Clyde Coombs in 1964 but currently not employed anywhere for elections for public office. Like in IRV, voters get a single vote and rank candidates in order of preference. If no candidate wins a majority of votes, the candidate with the most last preferences is excluded and another round of counting commences taking into account information from the excluded candidates' ballots.
Coombs‘ Method is like IRV in reverse because the only difference between IRV and Coombs‘ Method is the order in which non-elected candidates are excluded. Whereas, if after the first round of counting no candidate has a majority of votes, IRV excludes the candidate who has received the fewest votes, Coombs‘ Method excludes candidates by distributing all votes according to the least preferred candidate on the ballot and eliminates the candidate with the most last preferences (even if they simultaneously have the most first preferences). The excluded candidate‘s preferences are then re-distributed per IRV and a second round of counting occurs. This continues until a candidate with greater than 50% of the vote is found, that candidate being elected.
Full Preferential Voting (FPV)
Full Preferential Voting (FPV)
A truly majoritarian system for electing a single winner, either at-large or in districts, in which voters get a single vote and must rank all candidates in order of preference. To win a candidate must receive a majority of votes. Commonly used in Australia.
After voters cast their ballots, votes are tallied. Any ballot that does not rank all candidates* is invalid or "informal" and excluded from the count at the outset. If a candidate wins a majority of first rankings, they win. If no candidate wins a majority of first rankings, a second round of vote counting – an “instant run-off” commences. The candidate with the fewest first rankings is eliminated and ballots with that candidate as their top choice will have their next choice counted. Votes are tallied and the process continues until one candidate has more than half of the remaining vote.
*In most places where FPV is used, a ballot in which all but one candidate is ranked is valid, since the final ranking can be inferred.
Reading List
Reading List
Theoretical Grounding
Theoretical Grounding
Josep Colomer (2005) “It's Parties that Choose Electoral Systems (Or, Duverger's Laws Upside Down).”
Matthew S. Shugart and Rein Taagepera (2017) Votes from Seats: Logical Models of Electoral Systems.
Ranked Choice Voting Variants
Ranked Choice Voting Variants
MIT Election Data & Science Lab (2026) Ranked Choice Voting: Instant Runoff Voting Use in the United States
Jack Santucci (2021) “Variants of Ranked-Choice Voting from a Strategic Perspective.”
Sarah John and Leigh Hargreaves (2011) “The Alternative Vote in Australia: Exacerbating a Culture of Adversarialism?”
William Sanders (2012) “Alice's Unrepresentative Council: Cause for Intervention?” (about PBV).
Jack Santucci and Benjamin Reilly (2020) “Utah’s new kind of ranked-choice voting could hurt political minorities — and sometimes even the majority.”
U.S. Context
U.S. Context
Jack Santucci (2017, webinar) History of Ranked Choice Voting in the United States
U.S. Advocacy
U.S. Advocacy
FairVote (2026) Ranked Choice Voting.
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