The plurality voting system is a single-winner voting system often used to elect executive officers or to elect members of a legislative assembly which is based on single-member constituencies.
The most common system, used in Canada, India, the UK, and the USA, is simple plurality, first past the post or winner-takes-all, a voting system in which a single winner is chosen in a given constituency by having more votes than any other individual representative; there is no requirement that the winner gain a majority of votes.
In some countries such as France and most of Latin America a similar system is used, but there are two rounds: the "two-ballot" or "runoff election" plurality system. If any candidate in the first round gains a majority of votes, then there is no second round; otherwise, the two highest-voted candidates of the first round compete in a two-candidate second round or all candidates above a certain threshold in the first round compete in a two-, three- or four-candidate second round.
In political science, the use of the plurality voting system alongside multiple, single-winner constituencies to elect a multi-member body is often referred to as single-member district plurality or SMDP. Plurality voting is also variously referred to as winner-takes-all or relative/simple majority voting; however, these terms can also refer to elections for multiple winners in a particular constituency using bloc voting.
The works of Arend Lijphart use the term "majoritarian" systems, where a plurality voting system is one of the defining variables. These terms are thus sometimes used almost synonymously.
First past the post
The term first past the post
) was coined as an analogy
to horse racing
, where the winner of the race is the first to pass a particular point on the track (in this case a plurality
), after which all other runners automatically and completely lose (that is, the payoff is "winner-takes-all"). There is, however, no "post" that the winning candidate must pass in order to win, as they are only required to receive the largest number of votes in their favour. This sometimes results in the alternative name "furthest past the post".
Historically, FPTP has been a contentious electoral system, giving rise to the concept of electoral reform and a multiplicity of different voting systems intended to address perceived weaknesses of plurality voting.
Plurality voting is used in 43 of the 191 countries in the United Nations for either local or national elections. Plurality voting is particularly prevalent in the United Kingdom and former British colonies, including the United States, Canada and India. See Westminster system.
In single winner plurality voting, each voter is allowed to vote for only one candidate, and the winner of the election is whichever candidate represents a plurality
of voters, that is, whoever received the largest number of votes. This makes the plurality voting system among the simplest of all voting systems for voters and vote counting officials (it is however very contentious to draw district boundary lines in this system).
In an election for a legislative body, each voter in a given geographically-defined electoral district votes for one candidate from a list of candidates competing to represent that district. Under the plurality system, the winner of the election acts as representative of the entire electoral district, and serves with representatives of other electoral districts.
In an election for a single seat, such as president in a presidential system, the same style of ballot is used and the candidate who receives the largest number of votes represents the entire population. (The President in the United States is not directly elected by such a system, but rather by an Electoral College.)
Generally plurality ballots can be categorised into two forms. The simplest form is a blank ballot where the name of a candidate is written in by hand. A more structured ballot will list all the candidates and allow a mark to be made by a single candidate, however a structured ballot can also include space for a write-in candidate
Plurality voting is based on minimal information — a person's vote can be entirely represented by a binary choice, so anything can be used to signify a vote — the ancient Greeks would vote on ostracising someone by scratching the name of the person to be ostracised on a piece of pottery. Votes cast as physical objects can also create a realistic display of the election results, such as an array of candidates with jars filled with differently coloured beans, with the winner being the most-filled.
Examples of plurality voting
The election of a Member of Parliament
in the UK is a well known example of the First Past the Post electoral system. But the system is also used on a smaller scale.
The election for class president
For this example, consider the election for the president of a school class. Each class has a president, who sits on a school council. Further assume that, in this imaginary school, male and female students disagree with each other on most issues, and students prefer to vote for others of the same sex as themselves.
In our hypothetical election, there are three candidates: Amy, Brian and Cathy. Each class member gets a ballot, with these three names on it. Each voter must put an "X" by one of the names on their ballot.
After the election finishes, the papers are sorted into three piles--one for votes for Amy, one for votes for Brian, and one for votes for Cathy.
The largest pile decides the winner. If Amy's pile has 11 votes, Brian's has 16, and Cathy's has 13, Brian wins.
Notice that there were a total of 40 votes cast, and the winner had only 16 of them — only 40%.
Note that the class members (the "electors") only vote once, and their votes help to choose both a class president and a member of the school council (the same person).
The election for school council
Suppose that all the other classes hold similar elections. Across all the classes, 8 of the class presidents that were elected were girls, and 9 were boys. That makes the boys the overall winner. The only influence that the pupils in this particular class had was to vote for Amy, Brian or Cathy to represent themselves.
Some might argue that a boy won for this class because there were two girls, who "split the vote": some of the girls in the class voted for Amy and others for Cathy. Perhaps if Amy had not been a candidate, all the girls would have voted for Cathy and she would have won this class; this in turn would make the girls the winners of the whole council. This is known as the spoiler effect.
More complex example
Voting is accomplished whereby each voter in each city selects one city on the ballot (Memphis voters select Memphis, Nashville voters select Nashville, etc.) Votes are tabulated; Memphis is selected with the most votes (42%). Note that this system does not require that the winner have a majority, but only a plurality. Memphis wins because it has the most votes, even though 58% of the voters in this example preferred Memphis least. Notice that this problem does not hold anymore in the two-round system.
Plurality is often conflated with Single-winner voting systems
in general, in order to contrast it with Proportional Representation
. See the advantages there for other advantages of plurality in this context, such as regionalism and accountability.
Preservation of One Person One Vote principle
The arguments for a plurality voting system rely heavily on the preservation of the "one person, one vote" principle (often shortened to OMOV
for "one man, one vote" or more recently "one member, one vote"), as cited by the Supreme Court of the United States
, wherein each voter is only able to cast one vote in a given election, where that vote can only go to one candidate. Plurality voting systems elect the candidate who is preferred first by the largest number of voters. Other voting systems, such as Instant-runoff voting
or Single Transferable Vote
also preserve OMOV
, but rely on lower voter preference to arrive at a candidate earning either absolute majority
or droop quota
However, proponents of other systems, such as approval voting, point out that the OMOV principle was made to control the magnitude of districts; that each district must be relatively in proportion to one another in population. Approval voting does not actually represent some voters more than others, so the OMOV principle would be a weak one to discount it on. In any case, it could be argued approval voting grants one vote for each candidate to each voter - which they may choose not to cast, and cannot vote cumulate on one candidate.
The Constituency Link
Plurality voting does not require constituencies to be more than single member, whereas most proportional systems do. The fewer representatives are elected from an area, the smaller the division may be. A small constituency, as opposed to a large multiple member one, allegedly holds various advantages, including the concentration of the representative-voter link and the relationship of accountability. Additionally, in countries such as Israel where the whole country is treated as a single constituency and representatives are selected by party-lists, the constituency link is lost altogether.
To a much greater extent than many other electoral methods, plurality electoral systems encourage tactical voting
techniques, like "compromising". Voters are pressured to vote for one of the two candidates they predict are most likely to win, even if their true preference is neither, because a vote for any other candidate will be likely to be wasted and have no impact on the final result. This is known as Duverger's Law
In the Tennessee example, if all the voters for Chattanooga and Knoxville had instead voted for Nashville, then Nashville would have won (with 58% of the vote); this would only have been the 3rd choice for those voters, but voting for their respective 1st choices (their own cities) actually results in their 4th choice (Memphis) being elected.
The difficulty is sometimes summed up, in an extreme form, as "All votes for anyone other than the second place are votes for the winner", because by voting for other candidates, they have denied those votes to the second place candidate who could have won had they received them. It is often claimed by United States Democrats that Democrat Al Gore lost the 2000 Presidential Election to Republican George W. Bush because some voters on the left voted for Ralph Nader of the Green Party, who exit polls indicated would have preferred Gore to Bush 45 percent to 27 percent, with the rest not voting in Nader's absence.
Such a mentality is reflected by elections in Puerto Rico and its three principal voter groups: the Independentistas (pro-independence), the Populares (pro-commonwealth), and the Estadistas (pro-statehood). Historically, there has been a tendency for Independentista voters to elect Popular candidates and policies. This phenomenon is responsible for some Popular victories, even though the Estadistas have the most voters on the island. It is so widely recognised that the Puertoricans sometimes call the Independentistas who vote for the Populares "melons", because the fruit is green on the outside but red on the inside (in reference to the party colours).
Because voters have to predict in advance who the top two candidates will be, this can cause significant perturbation to the system:
- Substantial power is given to the media. Some voters will tend to believe the media's assertions as to who the leading contenders are likely to be in the election. Even voters who distrust the media will know that other voters do believe the media, and therefore those candidates who receive the most media attention will nonetheless be the most popular and thus most likely to be in one of the top two.
- A newly appointed candidate, who is in fact supported by the majority of voters, may be considered (due to the lack of a track record) to not be likely to become one of the top two candidates; thus, they will receive a reduced number of votes, which will then give them a reputation as a low poller in future elections, compounding the problem.
- The system may promote votes against more so than votes for. In the UK, entire campaigns have been organised with the aim of voting against the Conservative party by voting for either Labour or Liberal Democrats based on which is most popular in each constituency, regardless of the voters' opinions of the policies of these parties.
- If enough voters use this tactic, the first-past-the-post system becomes, effectively, runoff voting - a completely different system - where the first round is held in the court of public opinion.
A feature of the FPTP system is that invariably, voters can select only one candidate in a single-member district, whilst in multi-member districts they can never select more candidates than the number of seats in the district. Some argue that FPTP would work better if electors could cast votes for as many candidates as they wish. This would allow voters to "vote against" a certain despised candidate if they choose, without being forced to guess who they should vote for to defeat that candidate, thus eliminating the need for tactical voting. Such a system would also serve to reduce the spoiler effect. This system is called approval voting.
Effect on political parties
is a principle of political science
which predicts that constituencies that use first-past-the-post systems will become two-party systems
, given enough time.
First-past-the-post tends to reduce the number of political parties to a greater extent than most other methods, thus making it more likely that a single party will hold a majority of legislative seats. (In the United Kingdom, 18 out of 22 General Elections since 1922 have produced a majority government.) Single party rule enables quicker decision-making with less need for back and forth negotiation; some argue that this is an advantage.
Multi-party coalitions, on the other hand, require consent among all coalition partners to pass legislation, which gives small parties a disproportionate amount of power. In the UK, arguments for plurality often look to Italy where the frequent government changeovers are presented as undesirable. (This problem could be solved with separation of powers, in which the entire government didn't have to turn over just because it lost a vote.)
FPTP's tendency toward fewer parties and more frequent one-party rule can also produce disadvantages. One such disadvantage is that the government may not consider as wide a range of perspectives and concerns. It is entirely possible that a voter will find that all major parties agree on a particular issue. In this case, the voter will not have any meaningful way of expressing a dissenting opinion through his or her vote.
As fewer choices are offered to the voters, voters may vote for a candidate with whom they largely disagree so as to oppose a candidate with whom they disagree even more (See tactical voting above). The downside of this is that candidates will less closely reflect the viewpoints of those who vote for them.
It may also be argued that one-party rule is more likely to lead to radical changes in government policy that are only favoured by a plurality or bare majority of the voters, whereas multi-party systems usually require greater consensus in order to make dramatic changes.
are votes cast for losing candidates or votes cast for winning candidates in excess of the number required for victory. For example, in the UK General Election of 2005
, 52% of votes were cast for losing candidates and 18% were excess votes - a total of 70% wasted votes. This is perhaps the most fundamental criticism of FPTP, that a large majority of votes may play no part in determining the outcome. Alternative electoral systems attempt to ensure that almost all votes are effective in influencing the result and the number of wasted votes is consequently minimised.
The presence of spoilers
often gives rise to suspicions that manipulation of the slate
has taken place. The spoiler may have received incentives to run. A spoiler may also drop out at the last moment, inducing charges that such an act was intended from the beginning.
Disproportionate influence of smaller parties
Smaller parties can disproportionately change the outcome of an FPTP election by swinging what is called the 50-50% balance of two party systems, by creating a faction
within one or both ends of the political spectrum
which shifts the winner of the election from an absolute majority
outcome to a simple majority
outcome favouring the previously less favoured party. In comparison, for electoral systems using proportional representation
small groups win only their proportional share of representation. In the United States
, this mechanism falls within one major reasoning (USA, Voting act, 1970s) favoring two-party, First-past-the-post (FPTP) electoral systems.
See single-winner voting systems
for other disadvantages commonly associated with plurality, such as diminished representation, sweepout and other skewed results, and "safe seats".
Issues specific to particular countries
In August 2008, Sir Peter Kenilorea
commented on what he perceived as the flaws of a first past the post electoral system in the Solomon Islands
- "An[...] underlying cause of political instability and poor governance, in my opinion, is our electoral system and its related problems. It has been identified by a number of academics and practitioners that the First Past the Post system is such that a Member elected to Parliament is sometimes elected by a small percentage of voters where there are many candidates in a particular constituency. I believe that this system is part of the reason why voters ignore political parties and why candidates try an appeal to voters' material desires and relationships instead of political parties. [...] Moreover, this system creates a political environment where a Member is elected by a relatively small number of voters with the effect that this Member is then expected to ignore his party’s philosophy and instead look after that core base of voters in terms of their material needs. Another relevant factor that I see in relation to the electoral system is the proven fact that it is rather conducive, and thus has not prevented, corrupt elections practices such as ballot buying."
The United Kingdom
continues to use the first-past-the-post electoral system for general elections, and for local government elections in England and Wales. Changes to the UK system have been proposed, and alternatives were examined by the Jenkins Commission
in the late 1990s but no major changes have been implemented. Canada
also uses this system for national and provincial
elections. In May 2005 the Canadian province of British Columbia
had a referendum on abolishing single-member district plurality in favour of multi-member districts with the Single Transferable Vote
system after the Citizens' Assembly on Electoral Reform
made a recommendation for the reform. The referendum obtained 57% of the vote, but failed to meet the 60% requirement for passing. An October 2007 referendum in the Canadian province of Ontario
on adopting a Mixed Member Proportional
system, also requiring 60% approval, failed with only 36.9% voting in favour.
Wales, Scotland, Northern Ireland, the Republic of Ireland, Australia and New Zealand are notable examples of countries within the UK, or with previous links to it, that use non-FPTP electoral systems.
Recent examples of nations which have undergone democratic reforms but have not adopted the FPTP system include South Africa, almost all of the former Eastern bloc nations, Russia, Afghanistan and Iraq.
Where plurality voting is used
Countries that use this system to elect the lower or only house of their legislature include:
The plurality election system is used in the Republic of China on Taiwan for executive offices such as county magistrates, mayors, and the president, but not for legislative seats which used the single non-transferable vote system. This has produced an interesting party structure in which there are two broad coalitions of parties which cooperate in executive elections but which compete internally in legislative elections.
India uses a proportional representation system for its upper house.