Plurality voting refers to electoral systems in which the candidate in an electoral district who poll more than any other are elected.
Proportional representation (PR) refers to any 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 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.
Single non-transferable vote or SNTV is an electoral system used to elect multiple winners. It is a generalization of first-past-the-post, applied to multi-member districts with each voter casting just one vote. Unlike FPTP, which is a single-winner system, in SNTV multiple winners are elected, typically in electoral districts; additionally, unlike FPTP, SNTV produces mixed representation and makes it unlikely for a single party to take all the seats in a city or a set area, which can happen under FPTP.
The additional-member system (AMS) is a mixed electoral system under which most representatives are elected in single-member districts (SMDs), and the other "additional members" are elected to make the seat distribution in the chamber more proportional to the way votes are cast for party lists. It is distinct from parallel voting in that the "additional member" seats are awarded to parties taking into account seats won in SMDs, which is not done under parallel voting.
Mixed-member proportional representation is a mixed electoral system which combines local majoritarian elections with a compensatory tier of party list votes, which are used to allocate additional members in a way that aims to produce proportional representation overall. In most MMP systems, voters get two votes: one to decide the representative for their single-seat constituency, and one for a political party. Some countries use single vote variants of MMP, although this article focuses primarily on dual vote versions of MMP.
Open list describes any variant of party-list proportional representation where voters have at least some influence on the order in which a party's candidates are elected. This is as opposed to closed list, in which party lists are in a predetermined, fixed order by the time of the election and gives the general voter no influence at all on the position of the candidates placed on the party list.
An electoral district, also known as an election district, legislative district, voting district, constituency, riding, ward, division, electorate, or (election) precinct, is a subdivision of a larger state created to provide its population with representation in the larger state's constituency. That body, or the state's constitution or a body established for that purpose, determines each district's boundaries and whether each will be represented by a single member or multiple members. Generally, only voters (constituents) who reside within the district are permitted to vote in an election held there. District representatives may be elected by a first-past-the-post system, a proportional representative system, or another voting method. They may be selected by a direct election under universal suffrage, an indirect election, or another form of suffrage.
Elections in Mexico are held every 6 years to elect a president and every 3 years to elect a legislature. These elections determine who, on the national level, takes the position of the head of state – the president – as well as the legislature.
The Japanese political process has two types of elections.
Plurality block voting, also known as plurality-at-large voting, bloc vote or block voting (BV) is a non-proportional voting system for electing representatives in multi-winner elections. Each voter may cast as many votes as the number of seats to be filled. The usual result when the candidates divide into parties is that the most popular party in the district sees its full slate of candidates elected in a seemingly landslide victory.
Electoral reform is a change in electoral systems which alters how public desires are expressed in election results.
Semi-proportional representation characterizes multi-winner electoral systems which allow representation of minorities, but are not intended to reflect the strength of the competing political forces in close proportion to the votes they receive. Semi-proportional voting systems can be regarded as compromises between forms of proportional representation such as party-list PR, and plurality/majoritarian systems such as first-past-the-post voting. Examples of semi-proportional systems include the single non-transferable vote, limited voting, and parallel voting.
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 candidates or parties with the most votes takes all seats 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.
Scorporo is a partially compensatory, mixed-member majoritarian electoral system, sometimes referred to as a negative vote transfer system (NVT) whereby a portion of members are elected in single-member districts (SMDs) and a portion are elected from a list. It may be fully defined as a parallel voting system which excludes a portion of the SMD winners' votes in electing the proportional tier, to result in a more proportional outcome. The exclusion of a portion of the SMD winners' votes is what makes scorporo fundamentally different from parallel voting and somewhat closer to mixed member proportional representation, and thereby between the two in terms of proportionality. The system is only known to have been used in Italy and for a portion of the compensatory tier of the National Assembly of Hungary.
The Italian electoral law of 2017, colloquially known by the nickname Rosatellum bis or simply Rosatellum after Ettore Rosato, the Democratic Party (PD) leader in the Chamber of Deputies who first proposed the new law, is a parallel voting system, which acts as a mixed electoral system, with 37% of seats allocated using a first-past-the-post electoral system and 63% using a proportional method, with one round of voting. The Chamber and Senate of the Republic did not differ in the way they allocated the proportional seats, both using the largest remainder method of allocating seats.
General elections were held in Argentina on 27 October 2019, to elect the president of Argentina, members of the national congress and the governors of most provinces.
The mixed single vote (MSV) or positive vote transfer system (PVT) is a mixed-member electoral system, where voters cast a single vote in an election, which used both for electing a local candidate and as a vote for a party affiliated with that candidate according to the rules of the electoral system. Unlike the more widespread mixed proportional and mixed majoritarian systems where voters cast two votes, split-ticket voting is not possible in MSV.
