Part of the Politics series |
Electoral systems |
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Politicsportal |
An electoral system (or voting system) is a set of rules that determine how elections and referendums are conducted and how their results are determined.
Some electoral systems elect a single winner (single candidate or option), while others elect multiple winners, such as members of parliament or boards of directors.
The study of formally defined electoral methods is called social choice theory or voting theory, and this study can take place within the field of political science, economics, or mathematics, and specifically within the subfields of game theory and mechanism design.
Name(s) | Variations | Type of representation | Mixed? | Single/multi-winner | List / candidate-based system | Type of decision rule | Type of ballot | Number of votes / voter | Number of tiers (if mixed) |
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First-past-the-post (FPTP/FPP) [1] Single-member plurality (SMP/SMDP) | two-round system with lower than 50% requirement in first round | majoritarian | No | single-winner | candidate | plurality | single choice | 1 | — |
General ticket Party-block voting (PBV) | majoritarian | No | multi-winner | list | plurality | single choice | 1 | — | |
Plurality block voting (BV) plurality-at-large voting (multiple non-transferable vote, MTNV) | limited party block voting | majoritarian | No | multi-winner | candidate | plurality | multiple choice | =number of winners | — |
Limited voting (LV) limited block voting partial block voting (multiple non-transferable vote, MNTV) | limited party block voting | semi-proportional | No | multi-winner | candidate | plurality | multiple choice | <number of winners | — |
Single non-transferable vote (SNTV) | semi-proportional | No | multi-winner | candidate | plurality | single choice | 1 | — | |
Single transferable vote (STV) Hare–Clark electoral system [2] (proportional ranked-choice voting) [3] | semi-proportional / proportional | No | multi-winner | candidate | quota | ranked choice (ordinal voting) | 1 (effectively) | — | |
Instant-runoff voting (IRV) [4] (Alternative vote - AV) [5] (Ranked-choice voting - RCV) [6] (Single-transferable vote - STV) (Hare's method) [7] | contingent vote, | majoritarian | No | single-winner | candidate | majority | ranked choice (ordinal voting) | 1 (effectively) | — |
Two-round system (TRS) [8] Runoff voting | Non-partisan primary, | majoritarian | No | single-winner | candidate | majority | single choice | 1 (each round) | — |
Two-round block voting (majority block voting)(multiple non-transferable vote, MNTV) | majoritarian | No | multi-winner | candidate | majority | multiple choice | =number of winners (each round) | — | |
Multiple transferable vote (MTV) (Preferential block voting) | majoritarian | No | multi-winner | candidate | majority | ranked choice (ordinal voting) | =number of winners, effectively | — | |
Exhaustive ballot | majoritarian | No | single-winner /multi-winner | candidate | majority | single choice | 1 | — | |
Cumulative voting | panachage (certain types) | majoritarian / semi-proportional | No | single-winner /multi-winner | candidate | plurality | cumulative ballot | >1 | — |
Approval voting (AV) [9] | block approval voting | majoritarian | No | single-winner /multi-winner | candidate | plurality | multiple choice | any number (max. one for one candidate) | — |
Score voting Range voting | Approval voting (score voting 0-1) | majoritarian / semi-proportional | No | single-winner /multi-winner | candidate | plurality | score ballot(cardinal voting) | — | |
Borda count | majoritarian / semi-proportional | No | single-winner /multi-winner | candidate | plurality | ranked choice (ordinal voting) | — | ||
Condorcet method | Copeland's method, Dodgson's method, Kemeny–Young method, Minimax, Nanson's method, ranked pairs, Schulze method, Tideman's alternative methods | majoritarian | No | single-winner | candidate | majority against every candidate | ranked choice (ordinal voting) | — | |
Party-list proportional representation list-PR | Largest remainder Highest averages Binomial voting | semi-proportional / proportional | No | multi-winner | list (+ candidate, if open list) | quota or divisor method | single choice | 1 (effectively) | — |
Superposition - non-compensatory combination of FPTP + List-PR (Supplementary member system) | Two-round system + List-PR | semi-proportional | Yes | multi-winner(+ single-winner in districts) | candidate + list | mixed non-compensatory | single choice | 2 (each tier) | 2 |
Seat-linkage compensatory combination of FPTP + List-PR | mixed single vote version best-loser mixed-member proportional | semi-proportional / proportional | Yes | multi-winner(+ single-winner in districts) | candidate + list | mixed compensatory | single choice | 2 (each tier) | 2 |
Vote-linkage compensatory combination of FPTP + List-PR Positive vote transfer system (PVT) [12] (mixed single vote - MSV [13] ) (Additional member system - AMS) | negative vote transfer | semi-proportional / proportional | Yes | multi-winner(+ single-winner in districts) | candidate + list | mixed compensatory | single choice | 1 | 2 |
Dual member proportional (DMP) [14] | semi-proportional / proportional | Yes | multi-winner | list or candidate | plurality | single choice | 1 | 1 |
Electoral system for national legislatures (lower house or unicameral) |
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No election (e.g. Monarchy) |
An election is a formal group decision-making process by which a population chooses an individual or multiple individuals to hold public office.
Plurality voting refers to electoral systems in which a candidate who polls more than any other counterpart is elected. In systems based on single-member districts, it elects just one member per district and may also be referred to as first-past-the-post (FPTP), single-member plurality (SMP/SMDP), single-choice voting, simple plurality or relative majority. A system which elects multiple winners elected at once with the plurality rule, such as one based on multi-seat districts, is referred to as plurality block voting.
Proportional representation (PR) refers to a type of electoral system under which subgroups of an electorate are reflected proportionately in the elected body. The concept applies mainly to political divisions among voters. The essence of such systems is that all votes cast – or almost all votes cast – contribute to the result and are effectively used to help elect someone – not just a bare plurality or (exclusively) the majority – and that the system produces mixed, balanced representation reflecting how votes are cast.
Party-list proportional representation (list-PR) is a subset of proportional representation electoral systems in which multiple candidates are elected through their position on an electoral list. They can also be used as part of mixed-member electoral systems.
The two-round system (TRS), also known as runoff voting, second ballot, or ballotage, is a voting method used to elect a single candidate, where voters cast a single vote for their preferred candidate. It generally ensures a majoritarian result, not a simple-plurality result as under first past the post. Under the two-round election system, the election process usually proceeds to a second round only if in the first round no candidate received a simple majority of votes cast, or some other lower prescribed percentage. Under the two-round system, usually only the two candidates who received the most votes in the first round, or only those candidates who received above a prescribed proportion of the votes, are candidates in the second round. Other candidates are excluded from the second round.
The single transferable vote (STV), sometimes known as proportional ranked choice voting (P-RCV), is a multi-winner electoral system in which each voter casts a single vote in the form of a ranked-choice ballot. Voters have the option to rank candidates, and their vote may be transferred according to alternate preferences if their preferred candidate is eliminated or elected with surplus votes, so that their vote is used to elect someone they prefer over others in the running. STV aims to approach proportional representation based on votes cast in the district where it is used, so that each vote is worth about the same as another.
Strategic voting, also called tactical voting, sophisticated voting or insincere voting, occurs in voting systems when a voter votes for a candidate or party other than their sincere preference to prevent an undesirable outcome. For example, in a simple plurality election, a voter might gain a better outcome by voting for a less preferred but more generally popular candidate.
Voting is a method by which a group, such as a meeting or an electorate, convenes together for the purpose of making a collective decision or expressing an opinion usually following discussions, debates or election campaigns. Democracies elect holders of high office by voting. Residents of a jurisdiction represented by an elected official are called "constituents", and the constituents who choose to cast a ballot for their chosen candidate are called "voters." There are different systems for collecting votes, but while many of the systems used in decision-making can also be used as electoral systems, any which cater to proportional representation can only be used in elections.
First-past-the-post voting is an electoral system wherein voters cast a vote for a single candidate, and the candidate with the most votes wins the election. Analogous systems for multi-winner contests are known as plurality block voting or "block voting" systems; both FPTP and block voting are "plurality" systems in that the winner needs only a plurality of the votes and not an absolute majority. The term first-past-the-post is a metaphor from horse racing of the plurality-voted candidate winning such a race; the electoral system is formally called single-member plurality voting (SMP) when used in single-member districts, and informally called choose-one voting in contrast to ranked voting or score voting.
The Edmonton provincial electoral district also known as Edmonton City from 1905 to 1909, was a provincial electoral district in Alberta, Canada mandated to return members to the Legislative Assembly of Alberta from 1905 to 1917 and again from 1921 to 1959.
FairVote, formerly the Center for Voting and Democracy, is a 501(c)(3) organization that advocates electoral reform in the United States.
Instant-runoff voting (IRV) is a voting method used in single-seat elections with more than two candidates. Instead of voting only for a single candidate, voters in IRV elections can rank the candidates in order of preference. Ballots are initially counted for each elector's top choice, losing candidates are eliminated, and ballots for losing candidates are redistributed until one candidate is the top remaining choice of a majority of the voters. When the field is reduced to two, it has become an "instant runoff" that allows a comparison of the top two candidates head-to-head.
A single-member district is an electoral district represented by a single officeholder. It contrasts with a multi-member district, which is represented by multiple officeholders. Single-member districts are also sometimes called single-winner voting, winner-takes-all, single-member constituencies or single-member electorates.
Instant-runoff voting (IRV) is an electoral system that uses ranked voting. Its purpose is to elect the majority choice in single-member districts in which there are more than two candidates and thus help ensure majority rule. It is a single-winner version of single transferable voting. Formerly the term "instant-runoff voting" was used for what many people now call contingent voting or supplementary vote.
Electoral reform is a change in electoral systems which alters how public desires are expressed in election results.
An electoral system or voting system is a set of rules that determine how elections and referendums are conducted and how their results are determined. Electoral systems are used in politics to elect governments, while non-political elections may take place in business, non-profit organisations and informal organisations. These rules govern all aspects of the voting process: when elections occur, who is allowed to vote, who can stand as a candidate, how ballots are marked and cast, how the ballots are counted, how votes translate into the election outcome, limits on campaign spending, and other factors that can affect the result. Political electoral systems are defined by constitutions and electoral laws, are typically conducted by election commissions, and can use multiple types of elections for different offices.
A majoritarian electoral system is an electoral system where the candidate with the most votes takes the seat using the winner-takes-all principle and in this way provides majoritarian representation. However, there are many electoral systems considered majoritarian based on different definitions, including types of at-large majoritarian representation such as block voting or party block voting, but district-based majoritarian systems such as first-past-the-post voting (FPTP/SMP). Where two candidates are in the running, the one with the most votes will have a majority, but where there are three or more candidates, it often happens that no candidate takes a majority of the votes.
The term ranked voting, also known as preferential voting or ranked choice voting, pertains to any voting system where voters use a rank to order candidates or options—in a sequence from first, second, third, and onwards—on their ballots. Ranked voting systems vary based on the ballot marking process, how preferences are tabulated and counted, the number of seats available for election, and whether voters are allowed to rank candidates equally. An electoral system that utilizes ranked voting employs one of numerous counting methods to determine the winning candidate or candidates. Additionally, in some ranked voting systems, officials mandate voters to rank a specific number of candidates, sometimes all; while in others, voters may rank as many candidates as they desire.
The mixed ballot transferable vote (MBTV) refers to a type of vote linkage-based mixed-member electoral system where a group of members are elected on local (lower) tier, for example in single-member districts (SMDs). Other members are elected on a compensatory national (upper) tier from a list and voters cast a single ballot where they may indicate their preferences separately.
The spare vote is a version of single transferable voting applied to the ranking of parties, first proposed for elections in Germany in 2013. This preferential party system is a ranked proportional representation electoral system applying to political parties instead of individual candidates. The spare vote refers to a secondary vote (preference) of the voter, which only comes into play if the first preference for the political party preferred by the voter, is below the electoral threshold. In Germany, there were draft laws for the spare vote system in Saarland, Schleswig-Holstein and Brandenburg federal states, but they were not implemented.
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