Proportional Representation Glossary

Alternative Vote
see IRV
approval voting
A majority-take-all (non-PR) multiple-winner voting system.
Alternative Vote (see IRV).
choice voting
see STV
closed list
A form of List PR in which the order of candidates on the list is determined before the election.
Condorcet voting methods are single-winner methods that generally employ ranked ballots, and guarantee that they will elect a Condorcet winner, if one exists. A Condorcet winner is a candidate that beats every other candidate on a head-to-head basis. Named after the Marquis de Condorcet.
cumulative voting
A semi-proportional voting system in which the voter has multiple votes that can be cast one per candidate, all for a single candidate, or in other combinations.
Droop quota
In STV, the quota calculated as the number of ballots divided by one more than the number of seats to be filled. Depending on the specific STV method, the result may be rounded up. The Droop quota is by far the most common STV quota. See also Hare quota.
Direct-recording electronic. DRE voting equipment requires votes to be cast by means of electronic data entry, such as a touch screen, and records the vote electronically. DRE voting machines can print a voter-verifiable paper trail ( VVPT) to enable proper auditing.
first past the post
see FPTP
In a first-past-the-post (FPTP) system, the candidate (or candidates) receiving the largest number of votes wins the election. Most US elections, whether single- or multiple-winner, are FPTP.
Hare quota
In STV, the quota calculated as the number of ballots divided by the number of seats to be filled, and then rounded down. The Hare quota is no longer in common use. See also Droop quota.
Instant Runoff Voting
see IRV
Instant Runoff Voting (also called AV, or Alternative Vote). The single-seat version of STV. Used in San Francisco for mayoral and county supervisor elections.
limited vote
A semi-proportional multiple-seat voting system. A voter is limited to casting fewer votes than there are candidates. Known as SNTV if the number of votes allowed is one.
List PR
A form of PR in which the proportion of voters who vote for a particular list of candidates determines the proportion of seats that the list wins. Seats are allocated from each ordered list of candidates, hence the name. Lists are typically, but not necessarily, presented by political parties, so this system is sometimes called “party-list PR”. Depending on the particular system, the list order can be determined in advance (closed list), or by voter preference (open list).
More than half.
majority take all
Voting systems in which a majority (or often a plurality) of voters can control the entire outcome of an election, and smaller groups of voters can be excluded from representation.
Meek’s method
An advanced form of STV, named after its inventor, mathematician Brian Meek. A rule based on Meek’s method is used in New Zealand for some local elections.
mixed member
Mixed-member (or additional-member) PR is a variation on List PR in which one group of representatives is elected from single-member districts, and another set of representatives is elected via List PR, with list candidates used to make up any disproportionality resulting from the single-member seats.
open list
A form of List PR in which the the voter expresses a preference for a candidate as well as a list, thus improving that candidate’s chance of being elected.
party list PR
Another term for List PR, especially when the candidate lists are limited to parties, as opposed to non-party groups.
A plurality of voters is the largest group of voters voting for a particular candidate (or candidates), even though the group may not constitute an absolute majority
plurality take all
see majority take all
Proportional representation.
In STV, the number of votes required for a candidate to win a seat. Also called the threshold.
ranked ballot
A ballot on which the voter indicates their order of preference for a list of candidates. Ranked ballots are used in STV, IRV and Condorcet voting systems, among others.
Semi-proportional voting systems such as cumulative voting and SNTV achieve actual proportionality only when voters follow a specific, coordinated strategy.
Single Non-Transferable Vote
see SNTV
Single Transferable Vote
see STV
Single Non-Transferable Vote. A semi-proportional voting system in which a voter casts a single vote for a single candidate in a multiple-seat election. SNTV is the single-vote form of Limited Voting.
Single Transferable Vote. A method of proportional representation with ballots on which voters rank candidates in order of preference. Used for PR in New Zealand, Scotland, Ireland, Australia, Cambridge MA, and Minneapolis MN, among others. Also known as choice voting. In its single-winner (non-PR) form, STV is commonly known as AV (Alternative Vote) or IRV.
see STV
In STV, the votes received by a winning candidate in excess of the quota, or votes required to win a seat.
see quota
top-two runoff
A form of single-winner election in which the top two finishers from a first election round run in a second round to determine the single winner. In some implementations, the second voting round is not held if the winner of the first round receives an absolute majority of the votes.
Voter Verifiable Paper Trail. A paper record of an otherwise electronic ballot (see DRE), used in audits as evidence of voter intent. Sometimes “Voter Verified Paper Trail”, but we prefer not to assume actual verification.

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