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Proportional representation Party-list Electoral list open list closed list local lists Apportionment Sainte-Laguë D'Hondt Huntington–Hill Hare Droop Imperiali Hagenbach-Bischoff National remnant Highest averages Largest remainder Proportional forms of ranked voting Single transferable vote Gregory Wright Schulze STV CPO-STV Ranked party list PR Spare vote Proportional forms of cardinal voting Proportional approval voting Sequential proportional approval voting Method of Equal Shares Phragmen's voting rules Biproportional apportionment Fair majority voting Weighted voting Direct representation Interactive representation Liquid democracy
Mixed systems By type of representation Mixed-member majoritarian Mixed-member proportional Non-compensatory mixed systems Parallel voting Majority bonus Compensatory mixed systems Additional member system Mixed single vote (positive vote transfer) Scorporo (negative vote transfer) Mixed ballot transferable vote Alternative Vote Plus Dual-member proportional Rural–urban proportional
Other systems and related theory Semi-proportional representation Single non-transferable vote Limited voting Cumulative voting Binomial voting Other systems Multiple non-transferable vote Double simultaneous vote Proxy voting Delegated voting Indirect STV Liquid democracy Random selection (sortition, random ballot) Supermajority Social choice theory Arrow's theorem Gibbard–Satterthwaite theorem Public choice theory Veto Players List of electoral systems List of electoral systems by country Comparison of electoral systems Effects of electoral systems Political fragmentation Political efficacy Voter turnout
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Proportional representation (PR) characterizes electoral systems by which divisions in an electorate are reflected proportionately in the elected body. If 30% of the electorate support a particular political party, then roughly 30% of seats will be won by that party. The essence of such systems is that all votes contribute to the result: not just a plurality, or a bare majority, of them. Proportional representation requires the use of multiple-member voting districts (also called super-districts); it is not possible using single-member districts alone.^[1][2][3]

There are only two PR voting types: party list PR and the single transferable vote (STV).^[4][5] Mixed member proportional representation (MMP), a hybrid method that uses party list PR as its proportional component, and FPTP as its plurality component is considered a mixed system, which is a distinct voting system.^{[6][7][8][9]: 22 [10][11][12][13][14]}

With party list PR, political parties define candidate lists and voters vote for a list. The relative vote for each list determines how many candidates from each list are actually elected. Lists can be "closed", "open", or local; open lists allow voters to indicate individual candidate preferences and vote for independent candidates. Voting districts can be as large as a province or an entire nation.

The single transferable vote uses smaller districts, with voters ranking individual candidates in order of preference. During the count, as candidates are elected or eliminated, surplus or discarded votes that would otherwise be wasted are transferred to other candidates according to the preferences. STV enables voters to vote across party lines and to elect independent candidates.

Mixed member proportional representation (MMP), also called the additional member system (AMS), is a hybrid, two-tier,^{[2]: 118 [15]} system combining a non-proportional single-winner election and a compensatory regional or national party list PR one. Voters have two votes, one for their single-member district and one for the party list, the party list vote determining the balance of the parties in the elected body.^[2][16] Biproportional apportionment, first used in Zurich in 2006, is a two-tier method for adjusting an election's result to achieve overall proportionality.^[17] A further system produces near perfect proportionality by dispensing with voting altogether: the random selection of representatives from the populace, known as sortition. It was used in ancient Athens and the Venetian Republic and is still used today in the summons to jury duty. In recent years, it has received increasing academic attention.^{[18][19][20][21]}

Some form of proportional representation is used for national lower house elections in 94 countries, party list PR being the most widely used (85).^[22] MMP is used in seven lower houses, and STV, despite long being advocated by political scientists,^[2]: 71 is used in only two: Ireland, since independence in 1922,^[23] and Malta, since 1921;^[24] in the United States, party bosses were generally opposed to it because it transferred more power to the electorate when selecting independent candidates to put forward.^[25]

As with all electoral systems, there are overlapping and contentious claims in terms of its advantages and disadvantages.^[26]

PR systems in the broader family of voting systems

Most experts group electoral systems into 3 general categories:

• PR systems;
• mixed member systems; and
• plurality/majority or single-winner systems; ^{[26] [6][7][8][9]: 22 [10][11]}

Discussions about PR often include comparisons between PR and plurality/majority voting systems, comparisons between PR and mixed systems, and among different types of PR systems. Party list PR and STV are considered to be the only two PR systems. Mixed member systems include MMP and MMM, also known as parallel voting.^[2][16]

The extent to which mixed member systems yield proportional results depends upon the features of each system, but MMP has the potential to be highly proportional due to the compensatory way that list seats are distributed like other a mixed systems.^{[7][8][9][10][27]} MMM adds an element of proportionality to single-winner systems by the addition of list seats, but distributes only the list seats proportionately without compensating for disproportions in the distribution of single-winner seats.

Advantages and disadvantages

The case for proportional representation was made by John Stuart Mill in his 1861 essay Considerations on Representative Government:

In a representative body actually deliberating, the minority must of course be overruled; and in an equal democracy, the majority of the people, through their representatives, will outvote and prevail over the minority and their representatives. But does it follow that the minority should have no representatives at all? ... Is it necessary that the minority should not even be heard? Nothing but habit and old association can reconcile any reasonable being to the needless injustice. In a really equal democracy, every or any section would be represented, not disproportionately, but proportionately. A majority of the electors would always have a majority of the representatives, but a minority of the electors would always have a minority of the representatives. Man for man, they would be as fully represented as the majority. Unless they are, there is not equal government ... there is a part whose fair and equal share of influence in the representation is withheld from them, contrary to all just government, but, above all, contrary to the principle of democracy, which professes equality as its very root and foundation.^[1]

Most academic political theorists agree with Mill,^[10] that in a representative democracy the representatives should represent all segments of society.

Fairness

PR attempts to resolve the unfairness of majoritarian and plurality voting systems, where the largest parties receive an "unfair" "seat bonus" and smaller parties are disadvantaged and have difficulty winning any representation at all (Duverger's law). The established parties in UK elections can win formal control of the parliament with as little as 35% of votes (UK general election, 2005). In Canada, majority governments are regularly formed by parties with the support of under 40% of votes cast. Coupled with turnout levels in the electorate of less than 60%, this can lead to a party forming a majority government by convincing as few as one quarter of the electorate to vote for it. In the 2005 UK general election, for example, the Labour Party under Tony Blair won a comfortable parliamentary majority with the votes of only 21.6% of the total electorate.^[28]: 3 But PR systems with a high electoral threshold, or other features that reduce proportionality, are not necessarily much fairer: in the Turkish general election, 2002, using an open list system with a 10% threshold, 46% of votes were wasted.^[2]: 83

Single-winner systems can also disproportionately benefit regional parties that can win districts where they have a strong following, while other parties with national support but no strongholds, like the Greens, win few or no seats. An example is the Bloc Québécois in Canada that won 52 seats in the 1993 federal election, all in Quebec, on 18% of the national vote, while the Progressive Conservatives collapsed to two seats on 16% spread nationally.^[29] Similarly, in the 2015 UK General Election, the Scottish National Party gained 56 seats, all in Scotland, with a 4.7% share of the vote while the UK Independence Party, with 12.6% of the national vote, gained only a single seat.^[30]

Election of minor parties

The use of multiple-member districts enables a greater variety of candidates to be elected. The more representatives per district and the lower the minimum threshold of votes required for election the more minor parties can gain representation. In emerging democracies, inclusion of minorities in the legislature can be essential for social stability and to consolidate the democratic process.^[2]: 58

Critics, on the other hand, claim this can give extreme parties a foothold in parliament, sometimes cited as a cause for the collapse of the Weimar government. With very low thresholds, very small parties can act as "king-makers", holding larger parties to ransom during coalition discussions. The example of Israel is often quoted,^[2]: 59 but these problems can be limited, as in the modern German Bundestag, by the introduction of higher threshold limits for a party to gain parliamentary representation.

Another criticism is that the dominant parties in plurality systems, often looked on as "coalitions" or as "broad churches",^[31] can fragment under PR as the election of candidates from smaller groups becomes possible. Israel, again, and Brazil and Italy are examples.^{[2]: 59, 89} However, research shows, in general, there is only a marginal increase in the number of parties in parliament.^[32]

Open list systems and STV, the only PR system which does not require political parties,^[33] enable independent candidates to be elected. In Ireland, on average, about six independent candidates have been elected each parliament.^[34]

Coalitions

The election of smaller parties gives rise to the principal objection to PR systems, that they almost always result in coalition governments.^{[2]: 59 [10]}

Supporters of PR see coalitions as an advantage, forcing compromise between parties to form a coalition at the centre of the political spectrum, and so leading to continuity and stability. Opponents counter that with many policies compromise is not possible (for example funding a new stealth bomber, or leaving the EU). Neither can many policies be easily positioned on the left-right spectrum (for example, the environment). So policies are horse-traded during coalition formation, with the consequence that voters have no way of knowing which policies will be pursued by the government they elect; voters have less influence on governments. Also, coalitions do not necessarily form at the centre, and small parties can have excessive influence, supplying a coalition with a majority only on condition that a policy or policies favoured by few voters is adopted. Most importantly, the ability of voters to vote a party in disfavour out of power is curtailed.^[10]

All these disadvantages, the PR opponents contend, are avoided by two-party plurality systems. Coalitions are rare; the two dominant parties necessarily compete at the centre for votes, so that governments are more reliably moderate; the strong opposition necessary for proper scrutiny of government is assured; and governments remain sensitive to public sentiment because they can be, and are, regularly voted out of power.^[10] However, the US experience shows that this is not necessarily so, and that a two-party system can result in a "drift to extremes", hollowing out the centre,^[35] or, at least, in one party drifting to an extreme.^[36]

Nevertheless, on average, compared to countries using plurality systems, governments elected with PR accord more closely with the median voter and the citizens are more content with democracy.^[32]

Voter participation

Plurality systems usually result in single-party government because relatively few votes in the most finely balanced districts, the "swing seats", can transfer sufficient seats to the opposition to swing the election. More partisan districts remain invulnerable to swings of political mood. In the UK, for example, about half the constituencies have always elected the same party since 1945;^[37] in the 2012 US House elections 45 districts (10% of all districts) were uncontested by one of the two dominant parties.^[38] Voters who know their preferred candidate cannot win have little incentive to vote, and if they do their vote has no effect, it is "wasted".^[2]: 10

With PR, there are no "swing seats", most votes contribute to the election of a candidate so parties need to campaign in all districts, not just those where their support is strongest or where they perceive most advantage. This fact in turn encourages parties to be more responsive to voters, producing a more "balanced" ticket by nominating more women and minority candidates.^[29] On average about 8% more women are elected.^[32]

Since most votes count, there are fewer "wasted votes", so voters, aware that their vote can make a difference, are more likely to make the effort to vote, and less likely to vote tactically. Compared to countries with plurality voting systems, voter turnout improves and the population is more involved in the political process.^[2][29][32]

Gerrymandering

To ensure approximately equal representation, plurality systems are dependent on the drawing of arbitrary boundaries of their single-member districts, a process vulnerable to political interference, to gerrymandering. To compound the problem, boundaries have to be periodically re-drawn to accommodate population changes. Even apolitically drawn boundaries can unintentionally produce the effect of gerrymandering, reflecting naturally occurring concentrations.^[39] With pure PR systems, such as closed and open list PR, have no districts to gerrymander. PR systems with multiple-member districts such as local-list and STV are less prone to gerrymandering – research suggests five-seat districts are immune to gerrymandering.^[39] The district boundaries are less critical and so can be aligned with historical boundaries such as cities, counties, states, or provinces; population changes can be accommodated by simply adjusting the number of representatives elected. For example, Professor Mollison in his 2010 plan for STV for the UK set an upper limit of 100,000 electors per MP so that a constituency of 500,000 electors would have five seats (1:100,000) but one of 500,001 six seats (1:83,000). His district boundaries follow historical county and local authority boundaries, yet he achieves more uniform representation than does the Boundary Commission, the body responsible for balancing the UK's first-past-the-post constituency sizes.^[37][40]

Mixed member systems are susceptible to gerrymandering for the local seats that remain a part of such systems. Under MMM, there is no compensation for the effects that such gerrymandering might have. Under MMP, the use of compensatory list seats makes gerrymandering less of an issue. However, its effectiveness in this regard depends upon the features of the system, including the size of the regional districts, the relative share of list seats in the total, and opportunities for collusion that might exist. A striking example of how the compensatory mechanism can be undermined can be seen in the 2014 Hungarian parliamentary election, where the leading party, Fidesz, combined gerrymandering and a number of other tricks to contrive a two-thirds parliamentary majority from a 45% vote.^[41][42]

Link between constituent and representative

Proportional Representation Voting Systems

The disadvantage of all pure closed list and open list proportional representation systems is as districts do not exist, there is no link between voters and their parliamentary representative.^[43] An example of a closed list PR system is Israel, where the entire nation is a single zone.^[44][45] Therefore, residents within Israel do not have parliamentary representatives to meet their specific regional needs. The Netherlands, which uses an open-list PR system, also does not include delineated districts. The whole country forms one zone of 150 members, which means although the election results are proportional, the link between elected members and their geographic area is extremely weak.^[46] In the Dutch open list PR system, "It does not matter where these votes were cast; there are no electoral districts".^[47] In the 2006 and 2007 Ukrainian parliamentary elections, a single nationwide electoral zone was used.^[48] Likewise, the 2007 and 2011 Russian legislative election used a single nationwide electoral zone.^[49] In February 2014, Vladimir Putin signed into law the restoration of MMP— a mixed electoral system.^[50] With the exception of the local list PR system, candidates do not represent districts in List PR systems. As noted in the Electoral Reform Society of the United Kingdom, “Closed party lists are completely impersonal, weakening any link between the representative and a regional area”.^[51]

Single Transferable Vote (STV) retains constituencies as in FPTP, however multi-seat constituencies are used. These are significantly larger than FPTP districts as multiple districts are combined.^[52] Multi-member districts provide voters with a selection of parliamentary representatives to approach with their concerns. A voter may prefer to communicate with a MP in their district who is a member of the political party that he/she voted for.^[53]

Mixed Voting Systems

In a mixed member proportional representation, which is a hybrid system half way between proportional representation and plurality voting systems there are electoral ridings. However, they are approximately twice the size as the equivalent FPTP system. Residents of rural areas are most affected by the larger ridings.

Plurality Voting Systems

In the first past the post voting system, not only do candidates represent districts, they live in their respective constituencies. In the Canadian House of Commons, elected officials address the Speaker of the House and refer to each other by their riding names. For example, Liberal leader Justin Trudeau is referred to as the Member from Papineau. This ensures regional representation. Instant-runoff voting (IRV), also known as alternative vote (AV) retains the same constituencies as FPTP.^[51]

Attributes of PR systems

District magnitude

Academics agree that the most important influence on proportionality is an electoral district's magnitude, the number of representatives elected from the district. Proportionality improves as the magnitude increases.^[2] Scholars recommend voting districts of between three and seven members.^[4]

At one extreme, the Chilean Binomial system, a nominally proportional open-list system, uses two-member districts resulting in the election of one candidate from each of the two dominant political blocks, and so cannot be considered proportional.^[2]: 79

At the other, where the district encompasses the entire country, and with a low minimum threshold, highly proportionate representation of political parties can result, and parties gain by broadening their appeal by nominating more minority and women candidates.^[2]: 83

After the introduction of STV in Ireland in 1921 magnitude slowly diminished as more and more three-member constituencies were defined, benefiting the dominant Fianna Fáil, until 1979 when an independent boundary commission was established reversing the trend.^[54] In 2010, a parliamentary constitutional committee recommended a minimum magnitude of four.^[55] Nonetheless, despite relatively low magnitudes Ireland has generally experienced highly proportional results.^[2]: 73

In the FairVote plan for STV (which FairVote calls choice voting) for the US House of Representatives, three- to five-member super-districts are proposed.^[56] In Professor Mollison's plan for STV in the UK, four- and five-member districts are used, with three and six as necessary to fit existing boundaries.^[37]

Minimum threshold

The minimum threshold is the minimum vote required to win a seat. The lower the threshold the higher the proportion of votes contributing to the election of representatives and the fewer the votes wasted.^[2]

All electoral systems have thresholds, either formally defined or as a mathematical consequence of the parameters of the election.^[2]: 83

A formal threshold usually requires parties to win a certain percentage of the vote in order to be awarded seats from the party lists. In Germany and New Zealand (both MMP), the threshold is 5% of the national vote but both define an alternate threshold of constituency seats won, three in Germany, one in New Zealand. Turkey defines a threshold of 10%, the Netherlands 0.67%.^[2] Israel has raised its threshold from 1% (before 1992) to 1.5% (up to 2004), 2% (in 2006) and 3.25% in 2014.^[57]

In STV elections, winning the quota (ballots/(seats+1)) of first preference votes assures election. However, well regarded candidates who attract good second (and third, etc.) preference support can hope to win election with only half the quota of first preference votes. Thus, in a six-seat district the effective threshold would be 7.14% of first preference votes (100/(6+1)/2).^[37] The need to attract second preferences tends to promote consensus and disadvantage extremes.

Party magnitude

Party magnitude is the number of candidates elected from one party in one district. As party magnitude increases a more balanced ticket will be more successful encouraging parties to nominate women and minority candidates for election.^[58]

But under STV too many candidates can be counter-productive, splitting the vote and so losing seats. An example of this was identified in a ward in the 2007 Scottish local elections where Labour, putting up three candidates, won only one seat but where they would have won two had a candidate particularly favoured by Labour voters not stood.^[37] The same effect may have contributed to the collapse of Fianna Fáil in the 2011 Irish general election.^[59]

Others

Other aspects of PR can influence proportionality such as the size of the elected body, the choice of open or closed lists, ballot design, and vote counting methods.

Measuring proportionality

A number of ways of measuring proportionality have been proposed, including the Loosemore-Hanby Index, the Sainte-Laguë Index and the Gallagher Index. None of these fully support ranked voting.^[60][61]

Deviation from proportionality denotes the proportion of malapointment in a democratic process. The deviation is a mathematical relationship between the percentage of votes obtained by a political party and the percentage of parliamentary seats allocated to it. It is calculated by subtracting each party's vote share from its seat share, adding up the absolute values (ignoring any negative signs), and dividing by two.^{[62]: 4–6}

PR electoral systems

Party list PR

Party-list proportional representation systems are a family of voting systems emphasizing proportional representation (PR) in elections in which multiple candidates are elected (e.g. elections to parliament) through allocations to an electoral list. Party list PR can include a closed, open or local list. Party list PR is used in many countries, including: Finland (local list), Latvia (open list), Sweden (open list), Israel (closed list), Brazil (open list), the Netherlands (open list), South Africa (closed list), Democratic Republic of the Congo (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.^[63] Local lists were used to elect the Italian Senate during the second half of the 20th century. The Ukraine and Russia formerly used closed list PR, but have switched back to MMP.^[48][50]

Closed list PR

Closed list describes the variant of party-list proportional representation where voters can (effectively) only vote for political parties as a whole and thus have no influence on the party-supplied order in which party candidates are elected. In closed list proportional representation systems, parties each list their candidates according to direction from their party leaders.^[64] As noted in the Electoral Society of the United Kingdom, “As candidates are selected by the party leaders, they are likely to put 'safe' candidates near the top of the list, at the expense of traditionally under-represented groups”.^[51] Therefore, in a closed-list PR system, there is no mechanism for voters to eject candidates, so long as these candidates are supported by their party leader. Contrarily, is a FPTP system, party leaders themselves can lose their seats. In the 2011 Canadian general election, Liberal leader Michael Ignatieff and Bloc Quebecois leader Gilles Duceppe both lost their seats in what were considered safe seats. Ignatieff’s Etobicoke-Lakeshore riding and Duceppe’s Laurier-Sainte-Marie were both held by their respective parties for six consecutive elections.^[65] This would have been impossible in a closed-list PR system.

Pure proportional representation systems such as closed and open list do not use delineated electoral districts. For example, "Israel (closed list) and the Netherlands (open list) have no electoral districts and instead the entire country is treated as a single voting unit".^[66] This means that although the results are highly proportional, the link between the voters and their parliamentary representative is extremely weak.^[46]

Open List PR

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. In open list proportional representation systems, parties provide a list of candidates. Voters select both a party and a candidate within that party. In some open list PR systems, voters can rank which party members they want to vote for. As in all pure PR systems, there are "no districts, or zones of multi-member districts".^[43] List PR systems where candidates represent districts are known as local list.

Local List PR

A Localized list or local list is a technique used under systems of party-list proportional representation to determine which party candidates are elected from the party list. Local lists differ from open lists or closed lists. As with open lists, local lists allow the electorate to vote for individual candidates, but that preference is expressed through local or district level election processes. Closed lists do not allow voters to express such a preference. Voters vote only for the party.

Voting in local list systems takes place at the district level, where each party is represented by a single candidate. In this, the system resembles first-past-the-post or other single-winner systems. However, the candidate with the largest number of votes in their district is not necessarily the one that is elected. This is because of the proportionality requirement of the system.

Two-tier party list systems

Some party list proportional systems with open lists use a two-tier compensatory system, as in Denmark, Norway, and Sweden. In Denmark, for example, the country 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 which can be cast for an individual candidate or for a party list on the district ballot. To determine district winners, candidates are apportioned their share of their party's district list vote plus their individual votes. The compensatory seats are apportioned to the regions according to the party votes 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.^[67][68][69]

Biproportional apportionment

Biproportional apportionment is a two-tier mathematical method (iterative proportional fitting) for modifying an election result to achieve proportionality. It was proposed for elections by the mathematician Michel Balinski in 1989, and first used by the city of Zurich for its council elections in February 2006, in a modified form called "new Zurich apportionment" (Neue Zürcher Zuteilungsverfahren). Zurich had had to modify its party list PR system after the Swiss Federal Court ruled that its smallest wards, as a result of population changes over many years, unconstitutionally disadvantaged smaller political parties. With biproportional apportionment, the method of election, the use of open party lists, hasn't changed, but the way winning candidates are determined has. The proportion of seats due to each party is calculated according to their overall, city-wide, vote, and then the district winners are adjusted to conform to these proportions. This means that some candidates, who would otherwise have been successful, can be denied seats in favor of initially unsuccessful candidates, in order to improve the relative proportions of their respective parties overall. This peculiarity is accepted by the Zurich electorate because the resulting city council is proportional and all votes, regardless of district magnitude, now have equal weight. The system has since been adopted by other Swiss cities and cantons.^[17][70]

Balinski has proposed another variant, fair majority voting (FMV), for single-winner voting systems, specifically for the US House of Representatives, introducing proportionality while changing neither the plurality method of election nor the, possibly gerrymandered, district boundaries. The upper apportionment tier would be at the state level.^[70] In another proposal, for the UK parliament, whose elections are contested by many more parties, the authors note that parameters can be tuned to adopt any degree of proportionality deemed acceptable to the electorate. In order to elect smaller parties, a number of constituencies would be awarded to candidates placed fourth or even fifth in the constituency – unlikely to be acceptable to the electorate, the authors concede – but this effect could be substantially reduced by incorporating a third, regional, apportionment tier, or by specifying minimum thresholds.^[71]

Sortition

Sortition is the random selection of political representatives from a population. Within statistical tolerances, the selection proportionately represents the population perfectly, in all its variety; entrepreneurs, teachers, plumbers, women, ethnic minorities, retirees, liberals, socialists, conservatives etc., are all represented in proportion to their presence in society. It was used in ancient Athens where selection by lot was considered a characteristic of democracy. It was later used in the Venetian Republic and is still used today in the summons to jury duty. In the 21st century, sortition has been used to select members for special citizens' assemblies in Ontario, British Columbia, Iceland, Belgium and elsewhere, and the concept has received academic attention.^{[18][19][20][21]}

Single transferable vote

The single transferable vote (STV), also called choice voting,^[3][25] is a preferential voting system: voters rank candidates in order of preference. Voting districts usually elect three to seven representatives. The count is cyclic, electing or eliminating candidates and transferring votes until all seats are filled. A candidate is elected whose tally reaches a quota, the minimum vote that guarantees election. The candidate's surplus votes (those in excess of the quota) are transferred to other candidates at a fraction of their value proportionate to the surplus, according to the votes' preferences. If no candidates reach the quota, the candidate with the fewest votes is eliminated, those votes being transferred to their next preference at full value, and the count continues. There are many methods for transferring votes. Some early, manual, methods transferred surplus votes according to a randomly selected sample, or transferred only a "batch" of the surplus, other more recent methods transfer all votes at a fraction of their value (the surplus divided by the candidate's tally) but may need the use of a computer. Some methods may not produce exactly the same result when the count is repeated. There are also different ways of treating transfers to already elected or eliminated candidates, and these, too, can require a computer.^[72][73]

In effect, the method produces groups of voters of equal size that reflect the diversity of the electorate, each group having a representative the group voted for. Some 90% 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.^[37] Political parties are not necessary; all other PR voting systems presume that parties reflect voters wishes, and so give power to parties.^[72] STV satisfies the voting system criterion proportionality for solid coalitions – a solid coalition for a set of candidates is the group of voters that rank all those candidates above all others – and is therefore considered a system of proportional representation.^[72] 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,^[10]: 50 and STV has, for this reason, sometimes been labelled "quasi proportional".^[74]: 83 While this may be true when considering districts in isolation, results overall are proportional. In Ireland, with particularly small magnitudes, results are "highly proportional".^{[2]: 73 [23]} In 1997, the average magnitude was 4.0 but eight parties gained representation, four of them with less than 3% of first preference votes nationally. Six independent candidates also won election.^[54] STV has also been described as the most proportional system.^[74]: 83 The system tends to handicap extreme candidates because, to gain 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.^[75][76] Conversely, widely respected candidates can win election with relatively few first preferences by benefitting from strong subordinate preference support.^[37]

STV is used for two national lower houses of parliament, Ireland, since independence (as the Irish Free State) in 1922,^[23] and Malta, since 1921, long before independence in 1966.^[77] It is also used for all other elections in Ireland except for that of the presidency, for the Northern Irish assembly and European and local authorities, Scottish local authorities, some New Zealand and Australian local authorities,^[78] the Tasmanian (since 1907) and Australian Capital Territory assemblies, where the method is known as Hare-Clark,^[79] and the city council in Cambridge, Massachusetts, (since 1941).^[25][80]

Australian Senate STV

The term STV in Australia refers to the Senate voting system, a variant of Hare-Clark characterized by the "above the line" group voting ticket, a party list option. It is used in the Australian upper house, the Senate, and some state upper houses. Due to the number of preferences that are compulsory if a vote for candidates (below-the-line) is to be valid – for the Senate a minimum of 90% of candidates must be scored, in 2013 in New South Wales that meant writing 99 preferences on the ballot^[79] – 95% and more of voters use the above-the-line option, making the system, in all but name, a party list system.^[81][82][83] Parties determine the order in which candidates are elected and also control transfers to other lists and this has led to anomalies: preference deals between parties, and "micro parties" which rely entirely on these deals. Additionally, independent candidates are unelectable unless they form, or join, a group above-the-line.^[84][85] Concerning the development of STV in Australia researchers have observed: "... we see real evidence of the extent to which Australian politicians, particularly at national levels, are prone to fiddle with the electoral system".^[74]: 86 A parliamentary commission investigating the 2013 election, has proposed abolishing the group voting ticket, prohibiting preference transfers between lists but allowing voters to rank above-the-line party lists, and easing compulsory preference voting.^[86][87]

Mixed Electoral Systems

Mixed electoral systems, also known as hybrid systems or two-tier systems, use two levels of vote apportionment. The most prominent example is mixed member proportional representation (MMP), as used in Germany since 1949, a hybrid system combining single-winner districts with a compensating party list PR vote at the national level. Straight party list PR systems, too, can use two-tier apportionment, with party lists at the district level but apportioning seats at the district and national levels.^[2]: 118 Another two-tier system is biproportional apportionment, a method of proportionately balancing elections that has been adopted in some Swiss cities and cantons.

Mixed member proportional representation

Mixed member proportional representation (MMP) combines a single-district vote, usually first-past-the-post, with a compensatory regional or nationwide party list proportional vote. The system aims to combine the local district representation of FPTP and the proportionality of a national party list system. It was invented for the German Bundestag after the second world war and has spread to Lesotho, Mexico, Bolivia and New Zealand. The system is also used for the Welsh and Scottish assemblies where it is called the additional member system.^[16][88] Voters have two votes, one for their district representative and one for the party list, the list vote determining the relative strength of parties in parliament. After the district winners have been determined, sufficient candidates from each party list are elected to "top-up" each party to the overall number of parliamentary seats due to it according to its overall list vote. Before apportioning list seats, all list votes for parties which failed to reach the minimum threshold are discarded, the proportions for remaining parties improve. Also, any direct seats won by independent candidates are subtracted from the parliamentary total used to apportion list seats.^[89]

The system produces highly proportional representation of political parties, but proportionality can be compromised if the ratio of list to district seats is too low, it may then not be possible to completely compensate district seat disproportionality. Another problem can be how overhang seats are handled, district seats that a party wins in excess of the number due to it under the list vote. To preserve proportionality, other parties need to be awarded "balance seats", increasing the size of parliament by twice the number of overhang seats, but this is not always done. Until recently, Germany increased the size of parliament by the number of overhang seats but did not use the increased size for apportioning list seats. This was changed for the 2013 national election after the constitutional court rejected the previous law, not compensating for overhang seats had resulted in a negative vote weight effect.^[90] Lesotho, Scotland and Wales don't increase the size of parliament at all, and, in 2012, a New Zealand parliamentary commission also proposed abandoning compensation for overhang seats, and so fixing the size of parliament. At the same time, it would abolish the single-seat threshold – any such seats would then be overhang seats and would otherwise have increased the size of parliament further – and reduce the vote threshold from 5% to 4%. Proportionality would not suffer.^[2][91]

Alternative Vote Plus

The Alternative Vote Plus (AV+), or Alternative Vote Top-up, is a mixed voting system. AV+ was invented by the 1998 Jenkins Commission which first proposed the idea as a system that could be used for elections to the Parliament of the United Kingdom.^[92]

As the name suggests, AV+ is an additional member system which works in two parts: the 'AV' part and the 'plus' part. As in the Alternative Vote Instant-runoff voting system, candidates are ranked numerically in order of preference. The important difference is that an additional group of members would be elected through the regional party lists system to ensure proportionality; in typical proposals, these members are 15–20% of the whole body. More specifically, each voter would get a second vote to elect a county or regional-level representative from a list of candidates of more than one person per party. The number of votes cast in this vote would decide how many representatives from that county or region would go on to parliament.

Additional Member System

The Additional Member System (AMS) is a mixed voting system which uses semi-proportional representation in order that the makeup of the elected group more closely resembles the share of votes cast between different political parties than under non-proportional systems such as first past the post voting.

AMS is used in Scotland, Wales, the London Assembly, Hungary and Bolivia, and was used (in a modified format) in Italy.

Majority Bonus System

The Majority bonus system (MBS) is a form of semi-proportional representation used in some European countries. Its feature is a majority bonus which gives extra seats or representation in an elected body to the party or to the joined parties with the most votes with the aim of providing government stability.

It is used in Greece, Italy and San Marino.

History

One of the earliest proposals of proportionality in an assembly was by John Adams in his influential pamphlet Thoughts on Government, written in 1776 during the American Revolution:

It should be in miniature, an exact portrait of the people at large. It should think, feel, reason, and act like them. That it may be the interest of this Assembly to do strict justice at all times, it should be an equal representation, or in other words equal interest among the people should have equal interest in it.^[93]

Mirabeau, speaking to the Assembly of Provence on January 30, 1789, was also an early proponent of a proportionally representative assembly:^[94]

A representative body is to the nation what a chart is for the physical configuration of its soil: in all its parts, and as a whole, the representative body should at all times present a reduced picture of the people, their opinions, aspirations, and wishes, and that presentation should bear the relative proportion to the original precisely.

In February 1793, the Marquis de Condorcet led the drafting of the Girondist constitution which proposed a limited voting scheme with proportional aspects. Before that could be voted on, the Montagnards took over the National Convention and produced their own constitution. On June 24, Saint-Just proposed the single non-transferable vote, which can be proportional, for national elections but the constitution was passed on the same day specifying first-past-the-post voting.^[94]

Already in 1787, James Wilson, like Adams a US Founding Father, understood the importance of multiple-member districts: "Bad elections proceed from the smallness of the districts which give an opportunity to bad men to intrigue themselves into office",^[95] and again, in 1791, in his Lectures on Law: "It may, I believe, be assumed as a general maxim, of no small importance in democratical governments, that the more extensive the district of election is, the choice will be the more wise and enlightened".^[96] The 1790 Constitution of Pennsylvania specified multiple-member districts for the state Senate and required their boundaries to follow county lines.^[97]

STV, or, more precisely, an election method where voters have one transferable vote, was first invented in 1819 by an English schoolmaster, Thomas Wright Hill, who devised a "plan of election" for the committee of the Society for Literary and Scientific Improvement in Birmingham that used not only transfers of surplus votes from winners but also from losers, a refinement that later both Andræ and Hare initially omitted. But the procedure was unsuitable for a public election and wasn't publicised. In 1839, Hill's son, Rowland Hill, recommended the concept for public elections in Adelaide, and a simple process was used in which voters formed as many groups as there were representatives to be elected, each group electing one representative.^[94]

The first practical PR election method, a list method, was conceived by Thomas Gilpin, a retired paper-mill owner, in a paper he read to the American Philosophical Society in Philadelphia in 1844: "On the representation of minorities of electors to act with the majority in elected assemblies". But the paper appears not to have excited any interest.^[94]

A practical election using a single transferable vote was devised in Denmark by Carl Andræ, a mathematician, and first used there in 1855, making it the oldest PR system, but the system never really spread. It was re-invented (apparently independently) in the UK in 1857 by Thomas Hare, a London barrister, in his pamphlet The Machinery of Representation and expanded on in his 1859 Treatise on the Election of Representatives. The scheme was enthusiastically taken up by John Stuart Mill, ensuring international interest. The 1865 edition of the book included the transfer of preferences from dropped candidates and the STV method was essentially complete. Mill proposed it to the House of Commons in 1867, but the British parliament rejected it. The name evolved from "Mr.Hare's scheme" to "proportional representation", then "proportional representation with the single transferable vote", and finally, by the end of the 19th century, to "the single transferable vote".

A party list proportional representation system was devised and described in 1878 by Victor D'Hondt in Belgium. D'Hondt's method of seat allocation, the D'Hondt method, is still widely used. Victor Considerant, a utopian socialist, devised a similar system in an 1892 book. Some Swiss cantons (beginning with Ticino in 1890) used the system before Belgium, which was first to adopt list PR in 1900 for its national parliament. Many European countries adopted similar systems during or after World War I. List PR was favoured on the Continent because the use of lists in elections, the scrutin de liste, was already widespread. STV was preferred in the English-speaking world because its tradition was the election of individuals.^[98]

In the last Irish elections to the UK Parliament in 1919, STV was used in the University of Dublin constituency; two Independent Unionists were elected. STV has been in use since Irish independence. This has led to a series of coalition governments; there has not been a single-party government since after the 1989 election, and the last time a majority single party government was formed was in 1977. A mainly centrist party, Fianna Fáil, typically received 30%–50% of the vote while opposition parties, traditionally the centre-right Fine Gael and the centre-left Labour Party, were comparatively weak, however after the 2011 election this changed significantly with Fianna Fáil losing over half their proportion of the vote they received from the 2007 election, losing their position as largest party in the parliament for the first time since the 1932 election, becoming the third largest party after the 2011 election.

STV was used in Tasmania in 1907.

PR is used by more nations than single winner systems. Among the world's 35 most robust democracies with populations of at least two million people, only six use winner-take-all systems for elections to the legislative assembly (plurality, runoff or instant runoff); four use parallel systems; and 25 use PR.^[99]

PR dominates Europe, including Germany and most of northern and eastern Europe; it is also used for European Parliament elections. France adopted PR at the end of World War II, but discarded it in 1958; it was used for parliament elections in 1986. Switzerland has the most widespread use of proportional representation, which is the system used to elect not only national legislatures and local councils, but also all local executives. PR is less common in the English-speaking world; New Zealand adopted MMP in 1993, but the UK, Canada, India and Australia all use winner-take-all systems for legislative elections.

In Canada, STV was used by the cities of Edmonton and Calgary in Alberta from 1926 to 1955, and by Winnipeg in Manitoba from 1920 to 1953. In both provinces the alternative vote (AV) was used in rural areas. First-past-the-post was re-adopted in Alberta by the dominant party for reasons of political advantage, in Manitoba a principal reason was the underrepresentation of Winnipeg in the provincial legislature.^{[94]: 223–234 [100]}

STV has some history in the United States. Many cities, including New York City, once used it to break up the Democratic Party monopolies on elective office. Cincinnati, Ohio, adopted STV in 1925 to get rid of a Republican Party monopoly, but the Republicans returned the city to FPTP in 1957. From 1870 to 1980, Illinois used a semi-proportional cumulative voting system to elect its House of Representatives. Each district across the state elected both Republicans and Democrats year-after-year. Cambridge, Massachusetts, (STV) and Peoria, Illinois, (cumulative voting) continue to use PR. San Francisco had city-wide elections in which people would cast votes for five or six candidates simultaneously, delivering some of the benefits of proportional representation.

List of countries using proportional representation or mixed systems

Detailed information on voting systems applying to the first chamber of the legislature is maintained by the ACE Electoral Knowledge Network. This includes both a map and a detailed table by country. What follows is a more summary presentation on countries using proportional representation.

Further reading

Books

• Amy, Douglas J. (1993). Real Choices/New Voices: The Case for Proportional Representation Elections in the United States. Columbia University Press.
• Pilon, Denis (2007). The Politics of Voting. Edmond Montgomery Publications.
• Colomer, Josep M. (2003). Political Institutions. Oxford University Press.
• Colomer, Josep M., ed. (2004). Handbook of Electoral System Choice. Palgrave Macmillan.
• Pukelsheim, Friedrich (2014). Proportional Representation. Springer.
• Linton, Martin; Southcott, Mary (1998). Making Votes Count: The Case for Electoral Reform. London: Profile Books.
• Forder, James (2011). The case against voting reform. Oxford: Oneworld Publications. ISBN 978-1-85168-825-8.

Journals

• John Hickman and Chris Little. "Seat/Vote Proportionality in Romanian and Spanish Parliamentary Elections" Journal of Southern Europe and the Balkans Vol. 2, No. 2, November 2000

See also

• Apportionment (politics)
• Hare quota
• Index of politics articles
• Interactive representation
• Sainte-Laguë method
• Semi-proportional representation

References

External links

• Proportional Representation Library
• "Proportional representation" Center for Voting and Democracy
• Handbook of Electoral System Choice
• "Electoral Systems", World Policy Institute
• Quantifying Representativity Article by Philip Kestelman
• The De Borda Institute A Northern Ireland-based organisation promoting inclusive voting procedures
• Electoral Reform Society founded in England in 1884, the longest running PR organization. Contains good information about single transferable vote – the Society's preferred form of PR
• Electoral Reform Australia
• Proportional Representation Society of Australia
• Fair Vote Canada
• FairVote, USA
• Why Not Proportional Representation?
• Vote Dilution means Voters have Less Voice Law is Cool site
• Proportional Representation and British Democracy Debate on British electoral system reform
• Felsenthal, Dan S. (2010). "Review of paradoxes afflicting various voting procedures where one out of m candidates (m ≥ 2) must be elected" (PDF). Assessing Alternative Voting Procedures. London, UK: London School of Economics and Political Science. Retrieved October 9, 2011.