Proportional representation (PR) is achieved by any electoral system under which subgroups of an electorate are reflected proportionately in the elected body. The party make-up of the elected representatives reflects the party make-up of the votes cast. The concept applies to representation of political parties and also other divisions of voters.
The term is used for any of the various electoral systems that produce proportional representation. The aim of such systems is that all votes cast, or at least a large proportion, are used to elect someone and that each representative in an assembly is elected by a roughly equal number of votes, and thus all (or most) votes have equal weight. Under other election systems, a slight majority in a districtor even just a minority of votes when it forms a pluralityis all that is needed to elect a member or group of members. PR systems provide balanced representation to different factions, usually defined by parties, reflecting how votes were cast.
In PR systems where only a choice of parties is allowed, the seats are allocated to parties in proportion to the vote tally or vote share each party receives. Under open-list PR and single transferable voting, the winning candidates are elected both on personal appeal and party label.
Exact proportionality is never achieved under PR systems, except by chance. The use of electoral thresholds that are intended to limit the representation of small, often extreme parties reduces proportionality in list systems, and any insufficiency in the number of levelling seats reduces proportionality in mixed-member proportional (MMP) or additional-member systems. Under single-transferable-vote (STV) or party-list PR systems, districts with a small or moderate number of seats allow local representation but may reduce proportionality. Any use of districts dividing the electorate creates a possibility of somewhat disproportionate results. Other sources of disproportionality arise from electoral tactics, such as party splitting in some MMP systems, where the voters' true intent is difficult to determine.
Nonetheless, PR systems approximate proportionality much better than single-member plurality voting (SMP) and block voting. PR systems also are more resistant to gerrymandering and other forms of manipulation.
Some PR systems do not necessitate the use of parties; others do. The most widely used families of PR electoral systems are party-list PR, used in 85 countries; mixed-member PR (MMP), used in 7 countries; and single transferable vote (STV), used in Ireland, Malta, the Australian Senate, and the Indian Rajya Sabha. Proportional representation systems are used at all levels of government and are also used for elections to non-governmental bodies, such as corporate boards.
Basics
Proportional representation refers to the general principle found in any electoral system in which the popularly chosen subgroups (parties) of an electorate are reflected proportionately in the elected body. To achieve that intended effect, proportional electoral systems need to either have more than one seat in each district (e.g., single transferable vote or STV), or have some form of compensatory seats (e.g., mixed-member proportional representation apportionment methods).Ring, Robert (2014). Proportional-first-past-the-post: a Canadian model of proportional representation. Memorial university of Newfoundland. A legislative body such as an assembly or parliament may be elected proportionally, whereas there is no need for a single office (e.g., a president or mayor) to be elected proportionately if no votes are for parties.
In the European Parliament, for instance, each member state has a number of seats that is (roughly) proportional to its population, enabling geographical and national proportional representation. For these elections, all European Union (EU) countries also must use a proportional electoral system (enabling political proportional representation): When n% of the electorate support a particular political party or set of candidates as their favourite, then roughly n% of seats are allotted to that party or those candidates. All PR systems aim to provide some form of equal representation for votes but may differ in their approaches on how they achieve this.
Types
There are many different electoral systems that have been used or proposed to achieve proportional representation. Most can be classified as party-list PR, the single transferable vote, or mixed-member PR.
Party-list PR methods
Party-list PR is the most commonly used version of proportional representation. Each voter casts a vote for a single party and each party is allocated seats based on its share of the vote. The seats are assigned to party-affiliated candidates on the parties' electoral lists. The mechanism that allocates seats to the parties or lists is how these systems achieve proportionality.
A variety of list PR systems are in use today. Just a few party-list PR systems use overall country-wide vote counts. The Netherlands and Israel are the two main examples. Others count vote shares in separate districts and allocate seats in each part according to the party's vote count in the district. Denmark and some others use both, as a form of mixed member proportional.
Some common types of electoral lists are:
Closed list systems, where each party lists its candidates according to the party's candidate selection process. This sets the order of candidates on the list and thus, in effect, their probability of being elected. The first candidate on a list, for example, will get the first seat that party wins. Each voter casts a vote for a list of candidates. Voters, therefore, do not have the option to express their preferences at the ballot as to which of a party's candidates are elected into office. A party is allocated seats in proportion to the number of votes it receives. Ley de lemas, an intermediate system formerly used in Uruguay, where each party (Lema) presents several closed lists (sublemas), each representing a faction or specific platform. Seats are allocated to parties according to the parties' shares of votes, then to each sublema proportionally, by the order of the names on the list. Open list systems, where voters may vote, depending on the model, for one person, or for two or more, or vote for a party list but indicate their order of preference within the list. The relative popularity of individual candidates are used to allocate the seats, apart from the list. Votes determine which of the party's candidates are elected. Nevertheless, the number of candidates elected from each list is determined by the number of votes that the list receives or that the candidates on the list receive overall. Localized list systems, where parties divide their candidates in single member–like constituencies, which are ranked inside each general party list depending by their percentages. This method allows electors to judge every single candidate as in a first-past-the-post (FPTP) system. Two-tier party list systems, as in Denmark, Norway, and Sweden. These operate similarly to mixed-member proportional systems or additional member systems. For example, Denmark is divided into ten multiple-member voting districts arranged in three regions, electing 135 representatives. In addition, 40 compensatory seats are elected. Voters have one vote. It is cast for an individual candidate or for a party list on the district ballot. To determine district winners, parties are allocated district seats based on their district vote shares. Candidates in the district are apportioned their share of their party's district list vote plus their individual votes, and the most popular are elected to fill their party's seats. Compensatory seats are apportioned to regions according to the party vote share aggregated nationally, and then to the districts where the compensatory representatives are determined. In the 2007 general election, the district magnitudes, including compensatory representatives, varied between 14 and 28. The basic design of the system has remained unchanged since its introduction in 1920. The simplest list PR system is the schedule plan where multiple members are elected in a contest, and each voter casts a single vote, which is counted both for a specific candidate and also for a party list. The seats are filled with the most popular candidates of the most popular parties. If quota is used, surplus votes of early winners can be put in the party pool of votes for determination of later seats.Hoag, Effective Voting (1913), p. 20 SERIALSET-06536_00_00-036-0142-0000.pdf Retrieved 15 April 2026
List PR systems are used in Finland (open list), Latvia (open list), Sweden (open list), Israel (national closed list), Brazil (open list), Kazakhstan (closed list), Nepal (closed list) as adopted in 2008 in first CA election, the Netherlands (open list), Russia (closed list), South Africa (closed list), Democratic Republic of the Congo (open list), and Ukraine (open list). For elections to the European Parliament, most member states use open lists, but most large EU countries use closed lists, so that the majority of EP seats are distributed by those.As counted from the table in Local lists were used to elect the Italian Senate during the second half of the 20th century.
Example An example election where the assembly has 200 seats to be filled is presented below. Every voter casts their vote for the list created by their favourite party and the results of the election are as follows (popular vote). Under party-list PR, every party gets a number of seats proportional to their share of the popular vote.
PartyPopular voteParty-list PRSainte-Laguë methodNumber of seatsSeats %Party A43.91%8844%Party B39.94%8040%Party C9.98%2010%Party D6.03%126%TOTAL99.86%200100% This is done by a proportional formula or method: for example, the Sainte-Laguë methodthese are the same methods that may be used to allocate seats for geographic proportional representation (for example, how many seats each state gets in the US House of Representatives). Votes and seats often cannot be mathematically perfectly allocated, so some amount of rounding has to be done. The various methods deal with this in different ways, although the difference is reduced if there are many seatsfor example, if the whole country is one district. In practice, party-list PR is also more complicated than in the example, as list PR used by countries often use more than one district, two or three tiers (e.g. local, regional and national), open lists and electoral thresholds. Final seat allocations are frequently not proportional to the parties' vote share.
Single transferable vote (STV)
The single transferable vote is an older method than party-list PR, and it does not need to involve parties. Instead of the process used in list PR, where parties put forward ordered lists of candidates from which winners are drawn in some order, under STV voters vote directly for candidates, who run by name. Instead of each voter only marking their first preference, as in FPTP and list PR, under STV a voter has opportunity to rank two or more candidates by preference, with only one marked preference used to place the vote. Votes cast for candidates determine the winners by relative popularity either by achieving a quota or by relative plurality at the end of the vote count process.