Proportional representation
Proportional representation is achieved by any 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 term is also used for any of the various electoral systems that produce proportional representation. The aim of such systems is that all votes cast contribute to the result so that each representative in an assembly is mandated by a roughly equal number of voters, and therefore all votes have equal weight. Under other election systems, a slight majority in a districtor even simply 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. 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.
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 or additional-member systems. Under single-transferable-vote or party-list PR systems, small districts with few seats in each allow local representation but may reduce proportionality. 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 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, used in 7 countries; and single transferable vote, 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 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, or have some form of compensatory seats. A legislative body such as an assembly or parliament may be elected proportionally, whereas there is no need for a single office 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 proportional to its population, enabling geographical and national proportional representation. For these elections, all European Union countries also must use a proportional electoral system : 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.Just a few party-list PR systems use overall country-wide vote counts. These include the Netherlands and Israel. 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 presents several closed lists, 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 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.
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. Under party-list PR, every party gets a number of seats proportional to their share of the popular vote.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. 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, 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.STV uses preferential ballots. The ranking is used to instruct election officials as to how the vote should be transferred in case the first preference is marked for an unelectable candidate or for an elected candidate who has an excess of votes needed to guarantee election. Each voter casts one vote. The district used elects multiple members. Because parties play no role in the vote count, STV may be used for nonpartisan elections, as with the city council of Cambridge, Massachusetts. A large proportion of the votes cast are used to actually elect someone, so the result is mixed and balanced, with no one voting block taking much more than its due share of the seats. Where party labels are indicated, proportionality party-wise is noticeable.
Counting votes under STV is more complicated than under first-past-the-post voting, but the example belows shows how the vote count is performed and how proportionality is achieved in a district with 3 seats. In reality, districts usually elect more members than that in order to achieve more proportional results. A risk is that if the number of seats is larger than, for example, 10 seats, the ballot will be so large as to be inconvenient and voters may find it difficult to rank the many candidates, although 21 are elected through STV in some elections. In many STV systems, voters are not required to mark more choices than desired. Even if all voters marked only one preference, the resulting representation would be more balanced than under single-winner FPTP, due to each voter having just one vote and districts electing multiple members under STV.
Under STV, the quota, the share of the vote that guarantees election, is determined beforehand. The Droop quota is commonly used. In a three-seat district, any candidate who earns more than 25 percent of the vote is declared elected. Note that it is only possible for three candidates to each achieve that quota.
In Cambridge, under STV, 90 percent of voters see their vote help to elect a candidate, more than 65 percent of voters see their first-choice candidate elected, and more than 95 percent of voters see one of their top three choices win.
Other reports claim that 90 percent of voters have a representative to whom they gave their first preference. Voters can choose candidates using any criteria they wish; the proportionality is implicit. Another source states that, when STV was used between 1925 and 1955 in Cincinnati, 90 percent of voters saw their first choice elected or their vote used to elect a secondary preference, with about 60 to 74 percent of voters seeing their first choice elected, even if their vote was not used to elect that person because it was transferred on as a surplus vote.
STV does not require political parties; party-list PR and MMP systems both presume that parties reflect voters wishes, which Nicolaus Tideman argues gives too much power to party officials. STV satisfies the electoral system criterion proportionality for solid coalitionsa solid coalition for a set of candidates is the group of voters that rank all those candidates above all othersand is therefore considered a system of proportional representation.
However, the small district magnitude used in STV elections has been criticized as impairing proportionality, especially when more parties compete than there are seats available, and STV has, for this reason, sometimes been labelled "quasi proportional".
Even though Ireland has particularly small magnitudes, results of STV elections are "highly proportional". In its 1997 election, the average magnitude was 4. Eight parties gained representation, four of them with less than 3% of first-preference votes nationally. Six independent candidates also won election.
There have been claims made that STV handicaps certain extreme candidates because, to gain transfers based on back-up preferences and so improve their chance of election, candidates need to canvass voters beyond their own circle of supporters, and so need to moderate their views. This argument is made from the high natural threshold STV provides with low district magnitude.
Conversely, widely respected candidates can win election even if they receive relatively few first preferences. They do this by benefiting from strong subordinate preference support. Of course, they must have enough initial support so that they are not in the bottom rung of popularity or they will be eliminated when the field of candidate is thinned.
Charles Dodgson, the polymath logician and author, developed a passionate interest in voting methods. He believed STV to be fundamentally flawed, particularly regarding the allocation of "surplus" votes. His novel solution was to let the candidates themselves caucus and "club" votes together through the process of a negotiated consensus. As he stated:
May I, in conclusion, point out that the method advocated in my pamphlet would be at once perfectly simple and perfectly equitable in its result?
However, his entreaties to Lord Salisbury, leader of the United Kingdom's Conservative Party and future prime minister, to adopt "clubbing" were rejected in 1884 as "too sweeping a change". Subsequently, he joined with Thomas Hare and several Conservative and Liberal members of Parliament to found the Proportional Representation Society and to pursue STV.