Swing (United Kingdom)
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Swing, in the
politics of the United Kingdom The United Kingdom is a constitutional monarchy which, by legislation and convention, operates as a unitary parliamentary democracy. A hereditary monarch, currently King Charles III, serves as head of state while the Prime Minister of th ...
, is a number used as an indication of the scale of voter change between two
political parties A political party is an organization that coordinates candidates to compete in a particular area's elections. It is common for the members of a party to hold similar ideas about politics, and parties may promote specific ideological or p ...
. It originated as a mathematical calculation for comparing the results of two
Parliamentary constituencies An electoral (congressional, legislative, etc.) district, sometimes called a constituency, riding, or ward, is a geographical portion of a political unit, such as a country, state or province, city, or administrative region, created to provid ...
. The UK uses a
first-past-the-post First-past-the-post (FPTP)—also called choose-one, first-preference plurality (FPP), or simply plurality—is a single-winner voting rule. Voters mark one candidate as their favorite, or First-preference votes, first-preference, and the cand ...
voting system An electoral or voting system is a set of rules used to determine the results of an election. Electoral systems are used in politics to elect governments, while non-political elections may take place in business, nonprofit organizations and inf ...
. The swing (in
percentage point A percentage point or percent point is the unit (measurement), unit for the difference (mathematics), arithmetic difference between two percentages. For example, moving up from 40 percent to 44 percent is an increase of 4 percentage points (altho ...
s) is the percentage of voter support minus the comparative percentage of voter support corresponding to the same
electorate Electorate may refer to: * The people who are eligible to vote in an election, especially their number e.g. the term ''size of (the) electorate'' * The dominion of a prince-elector in the Holy Roman Empire until 1806 * An electoral district ...
or demographic. The swing is calculated by comparing the percentage of voter support from one election to another. The percentage value of the comparative elections results are compared with the corresponding results of the substantive election. An electoral swing analysis shows the extent of change in voter support from one election to another. It can be used as a means of comparison between individual candidates or political parties for a given electoral region or demographic.


Original mathematical calculation

The original mathematical construct
Butler A butler is a person who works in a house serving and is a domestic worker in a large household. In great houses, the household is sometimes divided into departments, with the butler in charge of the dining room, wine cellar, and pantries, pantr ...
swing is defined as the average of the Conservative Party percentage-point gain and Labour Party percentage-point loss between two elections, calculated on the basis of the total number of votes (including those cast for candidates other than Conservative or Labour). There is an alternative version called Steed swing which calculates the swing on the basis of votes cast for Conservative and Labour only. It is possible for the same election to have a Butler swing of one sign and a Steed swing of the other. As an example, assume that a constituency had two sequential election results as follows: The Butler swing to the Conservatives is therefore: The Steed swing is slightly more complicated to calculate, as it focuses on the shift between two specific parties (ignoring all others). In the above case, the swing to the Conservatives would be: Labour would have a corresponding loss in the same amount:


Creation

Swing was originated by David Butler, a political science academic at
Nuffield College, Oxford Nuffield College () is one of the Colleges of the University of Oxford, constituent colleges of the University of Oxford in England. It is a graduate college specialising in the social sciences, particularly economics, politics and sociology. N ...
. In a contribution to ''The British General Election of 1945'' he wrote "this measurement of 'swing', admittedly imperfect, does give us a broad idea of the movement of opinion from Conservative to Labour" and went on to compare the swings in each area of the country. The concept became important in the
general elections A general election is an electoral process to choose most or all members of a governing body at the same time. They are distinct from by-elections, which fill individual seats that have become vacant between general elections. General elections ...
of the 1950s when it was found that there was a relatively uniform swing across all constituencies. This made it easy to predict the final outcomes of general elections when few actual results were known, as the swing in the first constituencies to declare could be applied to every seat. Only a relatively small proportion of seats in most UK general elections are
marginal seat A marginal seat or swing seat is a constituency held with a small majority in a legislative election, generally one conducted under a single-winner voting system. In Canada, they may be known as target ridings. The opposite is a safe seat. T ...
s, and thus likely to change party. The swing enabled prediction of outcomes to be made even while
safe seat A safe seat is an electoral district which is regarded as fully secure, for either a certain political party, or the incumbent representative personally or a combination of both. With such seats, there is very little chance of a seat changing h ...
s were returning results whose victors were not in doubt. In several elections, such as 1970, the swing correctly predicted a majority for the then opposition even while government party victories seemed to predominate. Taking the national vote shares in an opinion poll could also easily be translated into likely seat outcomes. Election-night television programmes from 1955 have usually featured a device known as the "
swingometer The swingometer is a graphics device that shows the effects of the Swing (United Kingdom), swing from one party to another on United Kingdom, British UK General Elections, election results programmes. It is used to estimate the number of seats th ...
" which consisted of a pendulum which could point to the swing nationally and illustrate the outcome.


Problems and development

During the
postwar period A post-war or postwar period is the interval immediately following the end of a war. The term usually refers to a varying period of time after World War II, which ended in 1945. A post-war period can become an interwar period or interbellum, w ...
British politics was characterised by a strong
two-party system A two-party system is a political party system in which two major political parties consistently dominate the political landscape. At any point in time, one of the two parties typically holds a majority in the legislature and is usually referr ...
. Almost all voters who changed their preference from one election to another, swung between the two main parties. There has been a much greater variety in change since the re-emergence of three-party politics in the 1970s. The original calculation of swing did not make any allowance for other parties and when the votes for other parties rose, demands arose for a more sophisticated measurement. The continuation of the first-past-the-post system, and the tendency for smaller parties to only run in some constituencies, made it increasingly difficult to use measures of swing to predict results. The Liberals (and, later, Liberal Democrats) have been the main catalyst for this change, providing a credible nationwide alternative to the two main parties. The success of the SNP in Scotland and
Plaid Cymru Plaid Cymru ( ; , ; officially Plaid Cymru – the Party of Wales, and often referred to simply as Plaid) is a centre-left, Welsh nationalist list of political parties in Wales, political party in Wales, committed to Welsh independence from th ...
in Wales, especially in elections to the
Scottish Parliament The Scottish Parliament ( ; ) is the Devolution in the United Kingdom, devolved, unicameral legislature of Scotland. It is located in the Holyrood, Edinburgh, Holyrood area of Edinburgh, and is frequently referred to by the metonym 'Holyrood'. ...
and
Welsh Assembly The Senedd ( ; ), officially known as the Welsh Parliament in English and () in Welsh, is the devolved, unicameral legislature of Wales. A democratically elected body, Its role is to scrutinise the Welsh Government and legislate on devolve ...
, has also had an effect. Two other mass parties – the
Green Party A green party is a formally organized political party based on the principles of green politics, such as environmentalism and social justice. Green party platforms typically embrace Social democracy, social democratic economic policies and fo ...
, which emerged in the 1980s, and
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, which emerged in the 1990s – won no seats in Parliament until the Greens took
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in the 2010 general election, but have had a significant effect on the swing in certain areas, most notably the Greens in Brighton Pavilion. Swing has also been complicated since the 1970s as the constituent areas of the UK have become increasingly fractured. This has led to swings being very different in different areas – for instance, 1992 saw a swing to the
Scottish Conservatives The Scottish Conservative and Unionist Party (), known as Scottish Tories, is part of the UK Conservative Party (UK), Conservative Party active in Scotland. It currently holds 5 of the 57 Scottish seats in the House of Commons of the United Ki ...
in Scotland, but a swing to Labour in
South East England South East England is one of the nine official regions of England, regions of England that are in the ITL 1 statistical regions of England, top level category for Statistics, statistical purposes. It consists of the nine counties of england, ...
. At the same time, other parties began to win significant levels of representation in the
House of Commons The House of Commons is the name for the elected lower house of the Bicameralism, bicameral parliaments of the United Kingdom and Canada. In both of these countries, the Commons holds much more legislative power than the nominally upper house of ...
. This has led to swing becoming a measurement of the changes in votes of the two biggest parties in the constituency in question, rather than just Labour and the Conservatives. Simply substituting the Liberal Party for the Labour Party in the calculation provides a measure of a 'swing between Conservative and Liberal'. However election results showed that this was not a useful predictor in seats which were being fought by these parties. It came to be used as a measure of the significance of the change of the vote. Almost all published election results are derived from the
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results service which in recent years shows the swing as between the two parties that came first and second, rather than strictly between Conservative and Labour. For this reason, the direction of swing is explicitly stated, rather than simply indicated through the sign, as applies to Butler Swing.


Analysis of relative party strengths

As swing analysis can be applied to the results of any two parties relative to each other, it is possible to assess parties' relative strengths, as seen in analysis of the
2010 United Kingdom general election The 2010 United Kingdom general election was held on Thursday 6 May 2010, to elect 650 Members of Parliament (or MPs) to the House of Commons of the United Kingdom, House of Commons. The first to be held after the minimum age for candidates was ...
: Image:2010UKElectionLabConSwing.svg, Labour to Conservative swing Image:2010UKElectionLDConSwing.svg, Liberal Democrat to Conservative swing Image:2010UKElectionLabLDSwing.svg, Labour to Liberal Democrat swing


Measurements

Butler swings of more than 10 points are very rare. Taking UK politics after
1945 1945 marked the end of World War II, the fall of Nazi Germany, and the Empire of Japan. It is also the year concentration camps were liberated and the only year in which atomic weapons have been used in combat. Events World War II will be ...
exclusively (as that election occurred ten years after its predecessor, and in a completely different political climate), only the
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and
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general elections had a national swing of more than 10 points (−10.23 and –10.8 points, respectively). The table below shows the national swing across
Great Britain Great Britain is an island in the North Atlantic Ocean off the north-west coast of continental Europe, consisting of the countries England, Scotland, and Wales. With an area of , it is the largest of the British Isles, the List of European ...
, and the number of individual constituencies out of more than 600 which had a swing of more than 10 points. Conventional swing is much more volatile, and many more constituencies have large conventional swings. In addition, the conventional swing in a constituency where the top two candidates are not Conservative and Labour cannot be meaningfully compared with the national or regional swing.


See also

*
Landslide election A landslide victory is an election result in which the winning candidate or party achieves a decisive victory by an overwhelming margin, securing a very large majority of votes or seats far beyond the typical competitive outcome. The term became ...
*
Shy Tory factor "Shy Tory factor" is a name given by British opinion polling companies to a phenomenon first observed by psephologists in the early 1990s. They observed that the share of the electoral vote won by the Conservative Party (known colloquially as th ...


Further reading

* ''The British General Election of 1945'' by R. B. McCallum and Alison Readman (
Oxford University Press Oxford University Press (OUP) is the publishing house of the University of Oxford. It is the largest university press in the world. Its first book was printed in Oxford in 1478, with the Press officially granted the legal right to print books ...
, 1947) pages 263–65 * ''Political Change in Britain'' by David Butler and Donald Stokes (Macmillan, 1969) pages 140–51


References

{{DEFAULTSORT:Swing (Politics) Elections in the United Kingdom Psephology Political terminology in the United Kingdom