Swing
The change in vote share between two elections, measuring movement of support.
Short answer
What is Swing?
Swing measures the change in vote share for a party or candidate between two elections. It can be calculated for a constituency, a booth or an entire state, and is the standard way of describing electoral movement.
Definition
Swing measures the change in vote share for a party or candidate between two elections. It can be calculated for a constituency, a booth or an entire state, and is the standard way of describing electoral movement.
Why It Matters
Swing analysis at booth level identifies exactly where support was gained or lost, which is far more actionable than a constituency-level figure. Uniform swing assumptions are convenient and usually wrong; real swing is highly localised.
Example in Indian Elections
A constituency showing a 4% overall swing may contain booths swinging 15% one way and others swinging 8% the other. The average conceals the story; the distribution reveals it.
Related Terms
- Vote ShareThe percentage of total valid votes polled that a candidate or party receives.
- Stratified SamplingDividing a population into groups and sampling proportionately from each.
- Turnout PropensityThe modelled likelihood that a given voter will actually vote.
- Cross-TabulationBreaking survey results down by demographic or behavioural subgroups.
- Sampling Error / Margin of ErrorThe uncertainty inherent in estimating a population from a sample.
- Back-CheckRe-contacting a share of survey respondents to verify enumerator honesty.