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 electoral threshold, or election threshold, is the minimum share of all the votes cast that a candidate or political party requires to achieve before they become entitled to representation or additional seats in a legislature. This limit can operate in various ways, e.g. in party-list proportional representation systems where an electoral threshold requires that a party must receive a specified minimum percentage of votes, either nationally or in a particular electoral district, to obtain seats in the legislature. In single transferable voting, the election threshold is called the quota and it is possible to pass it by use of first choice votes alone or by a combination of first choice votes and votes transferred from other candidates based on lower preferences. In mixed-member-proportional (MMP) systems the election threshold determines which parties are eligible for top-up seats in the legislative body.
In political science, Duverger's law holds that in political systems with only one winner, two main parties tend to emerge with minor parties typically splitting votes away from the most similar major party. In contrast, systems with proportional representation usually have more representation of minor parties in government.
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.
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.
The D'Hondt method, also called the Jefferson method or the greatest divisors method, is an apportionment method for allocating seats in parliaments among federal states, or in proportional representation among political parties. It belongs to the class of highest-averages methods. The D'Hondt method reduces compared to ideal proportional representation somewhat the political fragmentation for smaller electoral district sizes, where it favors larger political parties over small parties.
The Webster method, also called the Sainte-Laguë method, is a highest averages apportionment method for allocating seats in a parliament among federal states, or among parties in a party-list proportional representation system. The Sainte-Laguë method shows a more equal seats-to-votes ratio for different sized parties among apportionment methods.
Parallel voting is a type of mixed electoral system in which representatives are voted into a single chamber using two or more different systems, most often first-past-the-post voting (FPTP) with party-list proportional representation (PR). It is the most common form of mixed member majoritarian representation (MMM), which is why these terms are often used synonymously with each other. In some countries, parallel voting is known as the supplementary member (SM) system, while in academic literature it is sometimes called the superposition method within mixed systems.
Rein Taagepera is an Estonian political scientist and former politician.
The Gallagher index measures an electoral system's relative disproportionality between votes received and seats in a legislature. As such, it measures the difference between the percentage of votes each party gets and the percentage of seats each party gets in the resulting legislature, and it also measures this disproportionality from all parties collectively in any one given election. That collective disproportionality from the election is given a precise score, which can then be used in comparing various levels of proportionality among various elections from various electoral systems. The Gallagher index is a statistical analysis methodology utilised within political science, notably the branch of psephology.
In electoral systems, a wasted vote is any vote that does not receive representation in the final election outcome.
Matthew Søberg Shugart is an American political scientist. He is a Distinguished Professor of political science at the University of California, Davis. He is also an Affiliated Professor at the University of Haifa. Shugart specializes in electoral systems, party systems, and the design of political institutions, primarily through empirical studies of political systems across large numbers of countries. Shugart is also an orchardist, and runs the Fruits and Votes blog on electoral systems and fruit growing.
In political science, the effective number of parties is a diversity index introduced by Laakso and Taagepera (1979) which provides for an adjusted number of political parties in a country's party system, weighted by their relative size. The measure is especially useful when comparing party systems across countries.
Elections to the Supreme Soviet were held in the Estonian SSR on 18 March 1990. Altogether 392 candidates ran for the Soviet-style legislature's 105 seats, of which four were pre-allocated to the military districts of the Soviet Army. The pro-independence Popular Front won the plurality. The coalition of the reformed Estonian communists, who favored independence but close relations with the USSR and were supported by Indrek Toome who was running under the Free Estonia banner, won 27 seats. The anti-independence, pro-Moscow "Joint Soviet of Work Collectives", representing mostly the ethnic Russian immigrant minority in Estonia, won 25 seats. During its first session, the new legislature elected the former Communist Party member Arnold Rüütel as its chairman, allowing him to stay as the nominal leader of Estonia.
Electoral reform is a change in electoral systems which alters how public desires are expressed in election results.
In voting theory, the micromega rule holds that, when political parties choose electoral systems, "the large prefer the small and the small prefer the large". The term "micromega" references Micromégas, a tale by Voltaire in which dwarfs and giants dialogue.
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 mixed electoral system or mixed-member electoral system combines methods of majoritarian and proportional representation (PR). The majoritarian component is usually first-past-the-post voting (FPTP/SMP), whereas the proportional component is most often based on party-list PR. The results of the combination may be mixed-member proportional (MMP), where the overall results of the elections are proportional, or mixed-member majoritarian, in which case the overall results are semi-proportional, retaining disproportionalities from the majoritarian component.
Political fragmentation is the fragmentation of the political landscape into different parties and groups, which makes it difficult to deliver effective governance. Political fragmentation can apply to political parties, political groups or other political organisations.
