{"id":6191,"date":"2025-04-27T23:50:45","date_gmt":"2025-04-27T22:50:45","guid":{"rendered":"https:\/\/marriott-stats.com\/nigels-blog\/?p=6191"},"modified":"2025-05-10T18:53:28","modified_gmt":"2025-05-10T17:53:28","slug":"weca-mayor-2025-election-forecast-2","status":"publish","type":"post","link":"https:\/\/marriott-stats.com\/nigels-blog\/weca-mayor-2025-election-forecast-2\/","title":{"rendered":"UK Local Elections #2B – 2025 West England Mayoral Election – My Final Forecast"},"content":{"rendered":"

The West England Combined Authority (WECA<\/strong>) Metro Mayor election of 2025<\/a> will probably be won with less than a quarter of all votes cast.\u00a0 My analysis shows it is a 5-way marginal, the likes of which have never been seen before in England.\u00a0 All five parties have reasons to be optimistic but as of now, I and most other forecasters make the Greens<\/strong> favourites to win the 2025 WECA<\/strong> mayoralty.\u00a0 With an election this tight, the parties get-out-the-vote efforts will play a big part in the final outcome.<\/p>\n

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All forecasts, charts & tables are based on the latest polls as of 26th April 2025.<\/em><\/span><\/p>\n

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My Forecast for the 2025 WECA Mayoral Election<\/strong> – Part 1<\/strong><\/span><\/h5>\n

This article is an update to my first forecast published on 14th April 2025<\/a><\/strong>.\u00a0 Please do read that if you haven’t done so since it covers the following points and what I write in part 2 is a continuation of what I wrote in part 1 –<\/p>\n

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  1. My election forecasting track record<\/span><\/li>\n
  2. What is the West England Combined Authority?<\/span><\/li>\n
  3. How has WECA voted since 2010?<\/span><\/li>\n
  4. Who is standing in 2025?<\/span><\/li>\n
  5. What do the latest polls say?<\/span><\/li>\n
  6. 4 Models to turn polls into predictions<\/span><\/li>\n
  7. What do the 4 models predict for 2025?<\/span><\/li>\n
  8. How did the 4 models perform in 2021?<\/span><\/li>\n
  9. Who will win the 2025 Mayoral Election?<\/span><\/li>\n
  10. Where my forecast could go wrong<\/span><\/li>\n
  11. My plea to pollsters<\/span><\/li>\n
  12. Other forecasts of the 2025 WECA mayoral election<\/span><\/li>\n<\/ol>\n

     <\/p>\n

    My Forecast for the 2025 WECA Mayoral Election – Part 2<\/strong><\/span><\/h5>\n

    I am calling this election a 5-way marginal with the Greens<\/span> most likely to win\"\"<\/strong>.\u00a0<\/strong> This was my conclusion two weeks ago and I have not changed my mind.\u00a0 There are minor changes though to the predicted vote shares of each party due to three changes I’ve made to my forecasting methodology.<\/p>\n

    The first is I am now taking a simple average of my 4<\/strong> models instead of a weighted average as before.\u00a0 I explain why I made this change in the next section but it is due to two WECA Mayor polls being published by YouGov<\/strong> & MoreInCommon<\/strong> plus a forecast made by an independent election forecaster Elections Predictor & Political Commentary<\/strong>.\u00a0 Links to these predictions are given in the next section.<\/p>\n

    The second reason is more polls have been published in the last two weeks and the estimated national shares of each party have changed slightly.\u00a0 The averages of the last 9<\/strong> national polls are shown on the right of the table below in two columns Incl<\/strong> & Excl<\/strong>.\u00a0 The difference comes from Incl<\/strong>uding or Excl<\/strong>uding the voting intentions of those who did not vote in the 2024 general election.\u00a0 I use Incl<\/strong> for my two models based on changes in the polls since the last mayoral election in 2021 and Excl<\/strong> for my two models based on changes in the polls since the last general election in 2024.\u00a0 More details of this distinction can be found in my forecast from two weeks ago.<\/p>\n

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    The third reason is I am now making separate estimates for each of the three unitary authorities of WECA<\/strong>, namely Bath & North East Somerset (B&NES<\/strong>), City of Bristol (Bristol<\/strong>) and South Gloucestershire (S.Glocs<\/strong>).\u00a0 I then combine the separate estimates to arrive at my final WECA forecast.\u00a0 This change was the result of feedback to my earlier forecast where it was pointed out to me that turnout in the 2021 mayoral election in Bristol was probably inflated due to local council elections being held at the same time.\u00a0 Since this is not happening in 2025, it is reasonable to expect Bristol turnout to be lower this time relative to B&NES and S.Glocs turnout.\u00a0 The only way to incorporate this effect is to apply my 4<\/strong> models to each authority separately so as to produce three separate forecasts before combining.\u00a0 This is what I have done in the table below.<\/p>\n

    On the left of the table, the total number of votes cast in WECA<\/strong> is broken down by the three unitaries for my 2025 forecast and the previous two mayoral elections in 2021 and 2017.\u00a0 On the right, I’ve repeated this breakdown for the last two general elections in 2024 and 2019 and the EU election in 2019.\u00a0 In 2019, the boundaries of the three unitaries mapped perfectly to the boundaries of 9<\/strong> parliamentary constituencies.\u00a0 However, the 2024 general election used new seat boundaries which no longer map perfectly to the three unitaries.\u00a0 This is why the title of the 2024 table states WECA now covers 9.4<\/strong> (strictly 9.38<\/strong>) seats.\u00a0 The brackets after each unitary name shows my estimate of how many seats map to that unitary.<\/p>\n

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    It is worth taking time to examine this table.\u00a0 In fact, I have made it available as a Microsoft Excel spreadsheet WECA Mayoral Election 2025 Forecast Builder<\/a><\/strong> so you can see the effect of changing various numbers on my forecast.\u00a0 To do this, edit the number of votes<\/strong> (not the vote shares) for each party within each local authority.\u00a0 All other figures such as share of vote, WECA total and grand totals will then change automatically.<\/p>\n

    Here is what I see in the table.<\/p>\n