Glossary

A family of electoral systems in which candidate(s) must receive a majority of votes to win. The most common versions of majoritarian voting in the United States are all single-winner, including Instant Run-off Voting, Majority Runoff, and Non-partisan Two Round Election Systems. 

Alternative Vote (AV): ➡️See "Instant Runoff"

Ballotage: ➡️See "Majority Runoff"

Instant Run-off (IRV)

A majoritarian variant of Ranked-choice Voting (RCV) 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 the "active" votes. For more detailed explanations, see DODO's RCV 101.  Also known as the “Alternative Vote” or "single-winner Ranked-choice Voting."

Full Preferential Voting

• The Australian variant of Instant Run-off Voting,  in which voters must rank all candidates to cast a valid ballot. As in IRV, a candidate must receive a majority of the total "active" votes cast to win. For more detailed explanations, see DODO's RCV 101. 

Majority Runoff

A single-winner majoritarian voting method in which voters select a single candidate and, if any one candidate receives a majority of votes cast, that candidate wins. If no candidate receives a majority of the vote in the general election, the two candidates with the most votes advance to a second round of voting: the runoff election. Whichever candidate receives the most votes in the runoff wins the seat. Also known as the “Two-round system” or "ballotage," it is used for some elections in several states including Louisiana, Georgia, and Mississippi. 

The majority runoff is closely related to the top-two primary, with three major differences:

• Timing:  The main election (with all of the candidates) occurs on general Election Day (and the runoff, if needed, afterwards).    

• Contingency of the second round: The runoff only occurs if no candidate wins in the general election.   

• Partisan primaries: State run partisan primary elections  can exist in a majority runoff system.   

Non-partisan two-round election system (NTES)

A non-partisan two-round election system (often called an "open primary" by advocates) works in two stages:

• "Winnowing" Preliminary Round: All candidates appear on one ballot with their self-selected party label. All voters receive this same ballot.

• General Election: The top vote-getters advance to the final ballot (no outside candidates can enter). If three or more advance, Ranked-choice Voting is often used be used.

Candidates choose the party designation they want next to their name on the ballot. Political party endorsements carry no official weight. 

Common types of NTES include: 

Top-five primary

• An NTES that uses the “winnowing” preliminary round to advance five candidates to the general election, and which uses IRV to determine the winner of the general election. 

Top-four primary

• An NTES that uses the “winnowing” preliminary round to advance four candidates to the general election, and which uses IRV to determine the winner of the general election. 

Top-two primary

• An NTES that uses the “winnowing” preliminary round to advance two candidates to the general election. In the general election, the candidate that wins a majority of votes wins office.  

• The top-two primary is closely related to Majority Runoff, with three major differences:

• • • Timing:  The main election (with all of the candidates) occurs before general Election Day (with the second round occurring on general Election Day).    

    • Inevitability of the second round: The second round always takes place on Election Day, unless only one candidate runs in the preliminary round.   

    • Partisan primaries: State run partisan primary elections cannot coexist with the top-two primary, as the top-two primary round replaces partisan primary elections.   

See DODO's Primary Elections 101 for more. 

Open Primary: ➡️See "Non-partisan two-round election system (NTES)" and "Partisan Primary"

Single-winner Ranked-choice Voting: ➡️See "Instant Runoff (IRV)"

Two-round system: ➡️See "Majority Runoff"

Multi-winner electoral systems that do not neatly fit into one of the other categories, but tend to produce pluralistic results (for example, electing multiple political parties or diverse candidates). Some of these systems are commonly called "semi-proportional." Common kinds of pluralistic electoral systems include cumulative voting, the limited vote, single nontransferable vote, and single transferable vote. 

Cumulative Voting 

A multi-winner system in which voters have the same number of votes as there are seats to be filled and can choose to allocate multiple votes to the same candidate. The candidates with the most cumulative votes win. Cumulative Voting was used to elect the Illinois state legislature from 1870 to 1980 and is currently in use in a few cities in the United States. 

Limited Vote 

A multi-winner system in which voters have fewer votes than there are seats to be filled and the candidates with the most votes win.  Voters cannot choose to allocate multiple votes to the same candidate.  Limited Voting is currently used in some local elections in the United States, especially in Alabama, Connecticut, Pennsylvania, and North Carolina. 

Mixed Member Majoritarian (MMM)

A mixed system in which seats in a legislative body are elected using two different logics. Typically, one set of seats in the legislature are elected using a proportional logic (such as party-list proportional representation) and others using a majority or plurality logic (using, for example, first-past-the-post, Plurality Block Vote, or Majority Runoff). Voters may get two votes, one for each class of seats, or the proportional seats may be allocated based on the party preference revealed in the majority or plurality contest. 

The number of proportional seats relative or plurality or majority varies, but MMM does not include formulae, top-up seats, or other adjustments to ensure overall proportionality of party votes to seats in the legislature.  This is the chief difference between MMM and Mixed Member Proportional. 

Multi-winner Ranked-choice Voting: ➡️See "Single Transferable Vote (STV)"

Proportional Ranked-choice Voting: ➡️See "Single Transferable Vote (STV)"

Semi-proportional: ➡️See "Pluralistic Systems"

Single Nontransferable Vote (SNTV)

A variant of the Limited Vote, in which voters have a single vote and the candidates with the most votes win. Used in Puerto Rico to elect the territorial legislature. 

Single Transferable Vote (STV)

A variant of Ranked-choice Voting 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. For more detailed explanations, see DODO's RCV 101. 

A family of electoral systems in which the candidate(s) with the most votes win, irrespective of whether the candidates have received a majority of votes. The two most common versions of plurality voting in the United States are First-past-the-post (in single-winner elections) and Plurality Block Voting (in multi-winner elections). 

At-large Voting: ➡️See "Plurality Block Vote"

Bloc(k) Vote: ➡️See "Plurality Block Vote"

First-past-the-post

A single-winner plurality voting method in which voters select a single candidate and the candidate with the most votes win, irrespective of whether the candidate received a majority of votes. Also known as “winner-take-all” voting or "single-member district plurality voting." It is commonly used in the United States, especially for congressional elections.  

Multi-member district plurality voting: ➡️See "Plurality Block Vote"

Plurality Block Vote

A multi-winner plurality voting method in which voters select up to as many candidates as there are to be elected and the candidates with the most votes win, irrespective of whether the candidates were selected by a majority of voters (or whether the same voters elect multiple or all candidates).  Also known as "At-large Voting" or "multi-member district plurality voting." It is commonly used in local elections in the United States, and for some state legislatures (including Maryland, New Hampshire, and North Dakota).  

Preferential Block Voting

A plurality multi-winner variant of Ranked-choice Voting, 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.  After each candidate is elected, the counting proceeds with the remaining candidates. For more detailed explanations, see DODO's RCV 101. 

Single-member district plurality voting: ➡️See "First-past-the-post"

Winner-take-all: ➡️See "First-past-the-post"

A family of multi-winner electoral systems in which seats in a legislature are assigned in proportion to a party or ticket's overall vote share in a geographic area. The most common types of proportional representation are Party-list Proportional and Mixed-Member Proportional. 

Alternative Vote (AV): ➡️See "Instant Runoff"

Ballotage: ➡️See "Majority Runoff"

Mixed Member Proportional (MMP)

A mixed single-winner and multi-winner proportional system in which voters vote for one candidate from a party or ticket. Every vote counts twice:  

1. For a local candidate in a single-winner district, typically using first-past-the-post to select the winner. 

2. For the candidate's party in a national at-large electorate, using party-list proportional representation.    

The number of district seats relative to the number of party-list proportional seats varies, but MMP always includes formulae, top-up seats, or other adjustments to ensure overall proportionality of party votes to seats in the legislature.  This is the chief difference between MMP and Mixed Member Majoritarian. 

Party-list Proportional Representation

A multi-winner proportional system in which voters cast ballots for one or more political parties and seats are filled in proportion to the party's vote share using "party lists". Party lists may be "closed," "open," or "partially open." 

Closed party list

• Political parties determine which and in what order their candidates are elected. Voters do not have any Election Day influence on the order in which a party's candidates are elected.  

Open party list

• Political parties determine the candidates and their order on the party list, but voters have the option to vote for one or more candidates and influence the order in which a party's list of candidates are elected. 

 For more detailed explanations, see DODO's Proportional Representation 101.  

Full Preferential Voting

• The Australian variant of Instant Run-off Voting,  in which voters must rank all candidates to cast a valid ballot. As in IRV, a candidate must receive a majority of the total "active" votes cast to win. For more detailed explanations, see DODO's RCV 101. 

In ranked or ordinal voting, voters rank candidates in order of their preference. Ranked voting describes only the way voters express their preferences, not the logic of representation they use. Ranked systems may be plurality, majoritarian, pluralistic, or proportional.  

Alternative Vote: ➡️See "Instant Runoff (IRV)"

Borda Count 

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. The system is named after its inventor, 18th century French mathematician Jean-Charles de Borda. A close variant of the Borda Count is used in parliamentary elections in Nauru  (see our Electoral Systems of the World dataset for more information).

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 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. For more detailed explanations, see DODO's RCV 101.

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.

Coombs' Method

A pluralistic single-winner variant of RCV 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. For more detailed explanations, see DODO's RCV 101. 

Instant Runoff (IRV)

A majoritarian single-winner variant of RCV, in which voters get a single vote and rank candidates in order of preference. To win a candidate must receive a majority of the "active" votes. For more detailed explanations, see DODO's RCV 101.  Also known as the “Alternative Vote” or "single-winner Ranked-choice Voting."

Preferential Block Voting

A plurality multi-winner variant of RCV, 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.  After each candidate is elected, the counting proceeds with the remaining candidates. For more detailed explanations, see DODO's RCV 101. 

Ranked-choice Voting (RCV)

A term used in the United States to describe ranked or ordinal voting methods, in which voters rank candidates in order of preference and votes are counted in rounds that sequentially elect or eliminate candidates and progressively draw on more information from voters’ ballots. When the term "RCV" is used without further qualification, it is typically a reference to Instant Runoff Voting. For more detailed explanations, see DODO's RCV 101. 

Multi-winner Ranked-choice Voting: ➡️See "Single Transferable Vote (STV)"

Proportional Ranked-choice Voting: ➡️See "Single Transferable Vote (STV)"

Single-winner Ranked-choice Voting: ➡️See "Instant Runoff (IRV)"

Single Transferable Vote (STV)

A variant of Ranked-choice Voting 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. For more detailed explanations, see DODO's RCV 101.