Single-winner voting system: Wikis


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A single-winner voting system is a voting system in which a predetermined constituency elects a single person to some office. Single winner voting systems that make use of electoral districts are also called single-member district systems.

If there is to be only one officeholder, often the case for executive positions such as president, mayor, or governor, single-winner systems are the only option. If there are several officeholders, such as when electing a legislature, then either a series of single-winner elections or a multiple-winner voting system can be used.

Examples of single-winner systems are plurality voting systems (first-past-the-post), two-round (runoff) systems, instant-runoff voting (IRV), approval voting, range voting, Borda count, and Condorcet methods (such as the Minimax Condorcet, Schulze method, and Ranked Pairs). Of these, plurality and runoff voting are the most commonly used in single-seat constituencies. Their advantages and disadvantages are often conflated with the advantages and disadvantages listed below.




Constituency link

Single-winner systems do not require constituencies to be more than single member, whereas most proportional systems do. 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. In non-single-winner 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.

Each representative must be a winner

Sometimes voters are in favour of a political party but do not like specific candidates. For example, voters re-elected the Alberta government in 1989 but, because of dissatisfaction with its leadership, the premier and leader of the governing party, Don Getty, lost his seat.

It is often claimed that because each electoral district votes for its own representative, the elected candidate is held accountable to his own voters, thereby helping to prevent incompetent, fraudulent or corrupt behavior by elected candidates. The voters in the electoral district can easily replace him since they have full power over who they want to represent them. In the absence of effective recall legislation, however, the electors must wait until the end of the representative's term. Moreover, it is possible for a winning candidate or government to increase support from one election to the next, but lose the election, or vice-versa. Also, it is generally possible for candidates to be elected if the party regards them as important even if they are fairly unpopular, by moving the candidate to a safe seat which the party is unlikely to lose or by getting a candidate in a safe seat to step down.

On the flip side, in a constituency system, a candidate who is popular nationally may be removed if he is unpopular in his own district. This feature, however, is also present in every proportional system in existence other than a closed party list.


First-past-the-post systems can benefit parties that are popular in one geographical region but have little support in other parts of the electorate. For example Plaid Cymru in Wales, and the Scottish National Party in Scotland both win seats in the United Kingdom parliament. In the 2006 Canadian election, the regional Bloc Québécois received 17 percent of the seats (51 seats) with 10 percent of the total votes. On the other hand single winner systems discriminate against parties that have a large amount of support that is spread thinly. For example in the German federal election of 2009 the Free Democrats won none of the 299 seats in the plurality portion of the election, but polled 15% of the vote in the list portion of the election allowing them to win 93 of the 622 seats available. The Liberal-Democrats of the United Kingdom suffer the same problem but without the remedial measure of the top up element to the election and the New Democratic Party received 9 percent of the seats (29 seats) with 17 percent of the total votes in the Canadian election of 2006.

Fewer minority parties

Single-winner systems tend to promote two-party systems (with some regional parties as noted above). Supporters view this as beneficial, as parliamentary governments or other coalitions are typically more stable in two-party systems, and thus small minorities are not given undue power to break a coalition. First-past-the-post minimizes the influence of third parties and thus arguably keeps out extremists. However, this can also deny fair representation to positive third parties, racial minorities, women, and others.


Effect on representation

Created by an organisation promoting proportional representation, this campaign postcard illustrates that Labour obtained a majority in Parliament despite winning only 35.2% of the national vote in the 2005 election.

The most commonly expressed disadvantage of first-past-the-post is that the winners of the election may not precisely reflect the distribution of votes, with substantial minority vote blocs ignored in their entirety, to the advantage of plurality winners. Thus, substantial bodies of opinion can be rendered irrelevant to the final outcome, and a party can obtain a majority of seats without a majority of the vote. Examples include the United Kingdom general election of 2005 where the new government won 55% of the seats with 35% of the national vote. The disproportionate nature of this system also means that whole regions may have MPs from only one party. The British Conservatives won large majorities of seats in the 1980s on a minority of votes while almost all the Scottish seats were Labour, Liberal or SNP; this disparity created tremendous dissatisfaction in Scotland.

An extreme example of disproportionality arose in Manitoba in the Canadian federal election of 1926. In most Manitoba seats, the non-Conservative parties did not stand candidates against each other, resulting in two-way contests between the Conservatives and one other party. The Conservatives received far more votes across the province than any other party, but won no seats.

Political party  % votes Number
of seats
 % seats
     Conservative 42.2% 0 0%
     Liberal-Progressive 19.5% 7 41%
     Liberal 18.4% 4 24%
     Progressive 11.2% 4 24%
     Labour 8.7% 2 12%

The usual cause for these disproportionate results is that a party has a large number of votes across the entire territory, but they are spread out across the territory rather than being concentrated in particular constituencies.[citation needed] Parties with less overall support, but where that support is concentrated in particular constituencies, will win plurality in those constituencies over a party with widely distributed support.

This presents a problem because it encourages parties to focus narrowly on the needs and well-being of specific electoral districts where they can be sure to win seats, rather than be sensitive to the sentiments of voters everywhere.[citation needed] A further problem is that the party in power often has the ability to determine where the boundaries of constituencies lie: to secure election results, they may use gerrymandering — that is, redistricting to distort election results by enclosing party voters together in one electoral district. Moreover, it can be demonstrated that even the use of non-partisan districting methods — such as computers — to determine constituency boundaries tends to generate results very similar to those produced by a majority party with the power to gerrymander in its favour.[1] Conversely, there are cases where there may be no possible way of drawing contiguous boundaries that will allow a minority representation.

Safe seats

A safe seat is one in which a plurality of voters support a particular candidate or party so strongly that a majority of votes for that candidate is practically guaranteed in advance of the election. This causes the difficulty that all other voters in the constituency can then make no difference to the result, since the winner of the seat is already known in advance. This results in feelings of disenfranchisement, and to abstentionism among voters.

As an example Gerry Adams of Sinn Féin holds the 4th safest parliamentary seat in Westminster for his West Belfast constituency.

Wasted votes

So-called wasted votes 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 single-winner systems when used for a legislature, that a large majority of votes may play no part in determining the outcome. Proportional representation systems attempt to ensure that almost all votes are effective in influencing the result and the number of wasted votes is consequently minimised. The theoretical minimum number of wasted votes under this definition is about 1/(n+1), where n is the number of seats elected by each fixed constituency; thus, a single-winner system has almost 50%, whereas elections for a hundred-member body could have under 1%.

Wipeout and clean sweep results

Since single member constituencies generate a winner's bonus, if not a winner-takes-all situation, the opposition can be left with few if any seats (see above).

It is argued that a weak or absent opposition due to an electoral wipeout is bad for the government. Provincial elections in several Canadian provinces provide suitable examples.


  1. ^ G. Gudgin; J. Taylor (1979). Seats, Votes and the Spatial Organisation of Elections. London, England: Methuen & Co.. 


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