Nigel Marriott's Blog

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By-Election Forecast #1 – Copeland, Cumbria

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Originally published on 19th February. Please scroll to the bottom for an updated forecast as of 22nd February.

The Conservatives are well set to take Copeland from Labour.  That is my forecast after running my by-election model on Copeland.  According to Matt Singh of NCP Politics, the last comparable by-election would be in 1878!  For more details about my methodology, please read how I forecast by-elections in the Brexit era.

As always, we need to start with a breakdown of the 2015 General Election results when Labour held the seat with a 6% majority and the 2016 EU referendum result where I estimate that Leave won with 61% of the vote.

My voter segmentation based on the Ashcroft “exit poll” shows Brexiteers account for 50% of all voters in 2016 but the majority of Labour voters were Remainers.  This perfectly encapsulates the dilemma for Labour in the North of England.  Do they double down on opposing Brexit and bring in additional Remainers to replace the Leavers they will lose or do they accept Brexit so as to hold to their Leavers and attempt to capture other Leavers who may have voted for them in the past?

For the other parties, their strategies are clear.  The Lib Dems will oppose Brexit and appeal to other Remainers using the success of Richmond Park as a springboard.  UKIP will try and make inroads in Labour Leavers.  For the Conservatives, they do not have as many Remainers to lose in the first place, especially the committed ones, so they can continue the path they are following and seek to attract other Leavers from other parties.

As I have stated before, the following voter dynamics are already apparent from the 3 contested by elections we have had since the referendum.

Witney & Richmond Park & Sleaford and North Hykeham

  • Pro-EU voters from all parties have defected to the Lib Dems.
  • Lib Dem Brexiteers have defected to the Conservatives.

Richmond Park & Sleaford only

  • Non-GE voters turnout is 1/3 of other party turnout.
  • A small national swing away from Labour of about 2% has occurred.

Witney & Richmond Park only

  • Best of Both voters have defected to Lib Dems, Conservative only in Witney, Labour & Conservative in Richmond.
  • Half of Bregret voters have defected to Lib Dems

The question now is which dynamics will be at play in Copeland and are there other dynamics that could come into play?  To answer the second question, there is one dynamic that is of great interest in both Copeland and the Stoke-on-Trent Central by-election which is taking place the same day and that is whether Labour Leave voters will defect to UKIP.  Therefore in my scenarios I have added a 7th dynamic as follows.

Not seen in 3 contested by-elections since Referendum

  • A quarter of Labour Brexiteers defect to UKIP.

There are many other dynamics that could come into play e.g. Green voters defect to Conservatives, but I have decided to only consider the 7 dynamics listed above.  In effect, I am saying that other dynamics not considered cancel each other out i.e. Conservatives defecting to Green would cancel out Greens defecting to Conservatives.

For some of the 7 dynamics I have allowed for a number of variants such as:

  • Either half or all of Best of Both voters defect to Lib Dems and such defectors may come from Conservatives only, Labour only or both Conservative & Labour.
  • The national swing away from Labour varies between 0% and 8% with the swingers splitting equally between Lib Dems and Conservatives.
  • 3 turnout models are used and are based on the 3 contested by elections we have had since the referendum. Richmond Park had the highest turnout whilst Sleaford had low turnout.

The national swing away from Labour is a hard one to get a handle on as from what I see in opinion polls there are considerable regional variations.  By taking the average of YouGov’s 4 polls between 10th January & 13th February, I have calculated the following swings from Labour since the 2015 General Election as shown in the table.

In the South (which contains Witney), there has been no change whereas in London (which contains Richmond Park) there has been a considerable swing to the Lib Dems.  In Scotland, the swing is to the Conservatives whilst in the Midlands and North, the swing is split between Conservatives and Lib Dems.

So I am now ready to run numerous scenarios based on various combinations of the 7 dynamics described and summarise the results.  In total, I ran 528 scenarios broken down into 3 broad groups as listed in this table.

The 3 groups of scenarios are:

  • LAST 3 BEs – 72 permutations of scenarios which are based on what was observed in the 3 contested by-elections. These do NOT include the 7th dynamic of Labour Brexiteers switching to UKIP.
  • VARIANTS – 144 permutations which are based on what was observed in the 3 contested by-elections and also include the 7th dynamic of Labour Brexiteers switching to UKIP.
  • OTHER – 312 permutations which were not observed in the 3 contested by-elections.

The table shows the average vote shares across the multiple scenarios and you can see that the Conservatives top all 3 groups.  But for me the more interesting figures are the % of scenarios where each party wins.  These show a clear pattern.

  • If Copeland follows the pattern of the 3 previous by elections, the Lib Dems have a 1 in 3 chance of winning the seat due to Best of Both voters defecting to them.
  • Labour’s best chance of winning comes from holding onto their Brexiteers & Best of Both voters.
  • If Labour Brexiteers start to defect to UKIP, then Labour’s chances sink and the Conservatives chances of winning rise considerably.
  • If other dynamics not seen before start to come into play then the Conservatives are almost certain to win the seat.

Having run all the scenarios, I have decided to stick my neck out and choose one scenario as my forecast which is shown in the 3rd row of table and shows a Conservative win by 3%.  This is based on the following assumptions.

  1. Voting dynamics will be closer to the Sleaford by-election since this is not a London seat.
  2. Sleaford saw no defections from Best of Both and Bregretters.
  3. There will be some Labour to UKIP defections among Brexiteers.
  4. Turnout patterns will be similar to Witney but with the addition of some Non-GE voters.
  5. An additional 4% swing away from Labour needs to be factored in.

Straightaway, you should be able to see that the last assumption is critical to the Conservatives winning under this scenario.  If Labour can buck the national swing then they can hold onto Copeland but if not, the Conservatives will be celebrating a major electoral feat.

UPDATED FORECAST AS OF 22/2/17

After I published this post, I was analysing some polls by YouGov and I came to the conclusion that there is an 8th dynamic that was present in both the Richmond Park and Sleaford by-elections.

Richmond Park & Sleaford only (additional)

  • Half of UKIP Potential Bregret defect to the Conservatives

This is not a large effect but I think it needs to be incorporated in my scenarios.

At the same time, I noticed that some scenarios that favour the Lib Dems had inadvertently been double counted and I eliminated my most extreme scenario in terms of additional national swing from Labour.  After rerunning the numbers, the revised forecast is now shown in this table.

The main change is that the outcome is extremely uncertain if Copeland follows one of the last 3 by-elections.  In essence, if it is a repeat of Richmond Park, then the Lib Dems can win, if it is a repeat of Witney, Labour will win and a repeat of Sleaford leads to a Conservative.

However, once you start considering Variants and Other scenarios, the odds shift markedly in favour of the Conservatives.

My chosen scenario is one that is similar what happened in Sleaford.