Winner's share
The average vote share of winning candidates.
How it's calculated
Mean share of the winning candidate, using single-member contests only so figures are comparable. A falling winner's share signals fragmentation.
Worked example
Heworth 2026 (single seat): the winner took 36.7%.
Source: Heworth ward, City of York — by-election of 15 January 2026 and May 2023.
Caveats
- Multi-member contests are excluded.
Where it's used
- Election Health (coming soon)
Other definitions
Vote shareChange in shareSwing (two-party, Butler)MajoritySwing needed to gainUncontested seatCandidates per seat / per wardContestation rateEffective number of partiesWinner's bonus (seats vs votes)Incumbency and re-election rateWomen candidates and councillorsTurnout (three methods)Council control and No Overall Control (NOC)Majority at riskPsephology National Share EstimateBy-election vote trackerNotional resultIndex of changeSplit-ticket indicatorNational Equivalent Vote