Swing (politics)

# Swing (politics)

Discussion

Encyclopedia
An electoral swing analysis (or swing) shows the extent of change in voter support from one election to another. It is an indicator of voter support for individual candidates or political parties, or voter preference between two or more candidates or parties. A swing can be calculated for the electorate as a whole, or for a given electoral district or demographic.

A swing is particularly useful for analysing change in voter support over time, or as a tool for predicting the outcome of elections in constituency-based systems.

## Calculation

A swing is calculated by comparing the percentage of the vote in a particular election to the percentage of the vote belonging to the same party or candidate at the previous election

Percentage of vote (current election) minus percentage of vote (previous election)

It can also be used in comparing a shift in voter intentions in analysing political polls.

### Example

An example is the comparison between the 2006
Ukrainian parliamentary election, 2006
The Ukrainian parliamentary election took place on March 26, 2006. Election campaigning officially began on July 7, 2005. Between November 26 and December 31, 2005 party lists of candidates were formed....

and 2007 Ukrainian Parliamentary elections
Ukrainian parliamentary election, 2007
Early parliamentary elections in Ukraine took place on 30 September 2007. The date of the election was determined following agreement between the President Viktor Yushchenko, the Prime Minister Viktor Yanukovych and the Chairman of the Verkhovna Rada Oleksandr Moroz on 27 May 2007, in an attempt...

.
Swing Analysis comparison Ukrainian Parliamentary Elections 2006 to 2007:

The above charts show the change in voter support for each of the six major political parties by electoral district and nationwide vote results.

The data is derived from the official published election results.

## Two-party swing

In some states, particularly Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

and its states and territories
States and territories of Australia
The Commonwealth of Australia is a union of six states and various territories. The Australian mainland is made up of five states and three territories, with the sixth state of Tasmania being made up of islands. In addition there are six island territories, known as external territories, and a...

, the swing is expressed in terms of two parties. This practice is most useful where a strong two-party system
Two-party system
A two-party system is a system where two major political parties dominate voting in nearly all elections at every level of government and, as a result, all or nearly all elected offices are members of one of the two major parties...

exists, and is used to predict the outcome of elections in constituency-based systems where different seats are held with different levels of support. Two assumptions underlie such a calculation: that a loss of support for one party is accompanied by an equivalent gain in support for the other, and that all districts will experience the same swing. Employing these two assumptions allows the analyst to compute an electoral pendulum, predicting how many (and which) seats will change hands given a particular swing, and what size uniform swing would therefore bring about a change of government.

## Australia

The term "swing" has a different meaning in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, which uses a preferential voting
Preferential voting
Preferential voting is a type of ballot structure used in several electoral systems in which voters rank candidates in order of relative preference. For example, the voter may select their first choice as '1', their second preference a '2', and so on...

system.

## United Kingdom

Swing in a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

political context is a single figure used as an indication of the scale of voter change between two political parties. It originated as a mathematical calculation for comparing the results of two constituencies. Britain, like the US, uses a first-past-the-post
First-past-the-post
First-past-the-post voting refers to an election won by the candidate with the most votes. The winning potato candidate does not necessarily receive an absolute majority of all votes cast.-Overview:...

voting system
Voting system
A voting system or electoral system is a method by which voters make a choice between options, often in an election or on a policy referendum....

.
The UK uses a two party swing calculation adding one party's percent rise to the fall of the other, and then dividing the total by two. So if party one's vote rises by 4% and party two's vote falls 5%, the swing is 4.5%.(ref: http://news.bbc.co.uk/1/hi/uk_politics/vote_2005/basics/4415923.stm#swing)

## United States of America

Swing in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

can refer to swing state
Swing state
In United States presidential politics, a swing state is a state in which no single candidate or party has overwhelming support in securing that state's electoral college votes...

, those states that are known to shift in outcome between Democrats
Democratic Party (United States)
The Democratic Party is one of two major contemporary political parties in the United States, along with the Republican Party. The party's socially liberal and progressive platform is largely considered center-left in the U.S. political spectrum. The party has the lengthiest record of continuous...

and Republican
Republican Party (United States)
The Republican Party is one of the two major contemporary political parties in the United States, along with the Democratic Party. Founded by anti-slavery expansion activists in 1854, it is often called the GOP . The party's platform generally reflects American conservatism in the U.S...

Parties. Other States are considered non-swing states, similar to the UK concept of safe seat
Safe seat
A safe seat is a seat in a legislative body which is regarded as fully secured, either by a certain political party, the incumbent representative personally or a combination of both...

s, as they rarely change in outcome. The extent of change in political outcome is heavily influenced by the voting system
Voting system
A voting system or electoral system is a method by which voters make a choice between options, often in an election or on a policy referendum....

in use; as in the UK, the US employs a first-past-the-post
First-past-the-post
First-past-the-post voting refers to an election won by the candidate with the most votes. The winning potato candidate does not necessarily receive an absolute majority of all votes cast.-Overview:...

voting system.