General election forecast
South West Hertfordshire
Predicted winner: Conservative with 26.1% of the vote, a 0.7pp margin over Lib Dem.
Predicted vote share
How the model expects this constituency to vote
Coloured number is the swing from the 2024 general election result.
Sitting MP
Gagan Mohindra
- Party: Conservative and Unionist Party
- Tenure: 1.9 years (since 2024-07-04)
- Status: standing again
See also: TheyWorkForYou
2024 general election result
What happened on 4 July 2024
| Candidate | Party | Votes | Share |
|---|---|---|---|
| Gagan Mohindra | Conservative and Unionist Party | 16,458 | 34.1% |
| Sally Symington | Lib Dem | 12,002 | 24.9% |
| Alex Sufit | Labour Party | 9,637 | 20.0% |
| Keith Steers | Reform UK | 6,790 | 14.1% |
| Narinder Sian | Green Party | 2,532 | 5.2% |
| Bernadette O'Malley | Party Of Women | 295 | 0.6% |
| Victor Silkin | Rejoin EU | 232 | 0.5% |
| Michael McGetrick | Social Democratic Party | 158 | 0.3% |
Source: Returning officer declaration
How accurate is the model here?
Our 2024 backtest for this constituency
We replayed the same model architecture against the 4 July 2024 general election using only the data a forecaster running the model in May 2024 would have known. Here's what it would have predicted for South West Hertfordshire, and what actually happened.
Predicted
Actual on 4 July 2024
Positive gap = we predicted that party would win more share than they did. See the full GE backtest across all 650 seats for the model's national accuracy.
How this forecast was built
- GE2024 Baseline. Actual GE2024 result in South West Hertfordshire
- National Swing (Strong Transition Model). Multiplicative bounded swing, losers shed in proportion to local share, gainers absorb pro-rata national gain. Replaces additive UNS.
- BES MRP Prior. Baseline blended with BES Wave 1-30 east_of_england prior at weight 5%
- English-identity floor. English 29.0% → Reform +1.0pp
- Normalise. Shares scaled to 100%