UK General Election Prediction

Ballot BoxI wrote a week or so ago about using some statistical methodology to try and predict the forthcoming General Election in the UK. I’ve now undertaken my first run of the model I developed and the results are below.

Remember, the model works on the following basis:

  1. A statistical model that looks at historical trends for each party of the movement of the polls from x months before the election to the actual point of the election
  2. Multi-variate analysis looking at the spread of the party’s support in the current polls
  3. Based on 1 and 2, a projection simulation of the actual election next year. I run 2,000 random simulations and analyse the results to produce the results below.

Remember, the model is based on the party’s opinion poll support moving as expected before the next General Election. If the support doesn’t move as expected over the next few months then the model will self-correct and respond to the new situation.

Initial Prediction

The following table is the mid-point prediction – i.e. of the 2,000 simulations this is the most likely outcome.

Party Vote % Seats Prediction Range (95% CI)
Conservatives 37.3 332 311 – 343
Labour 31.3 262 233 – 290
Liberal Democrats 16.1 13 7 – 21
UKIP 3.9 0 0
SNP/PC 2.9 20/4 9 – 40 / 2 – 7
Others 8.5 19 n/a

Other specific predictions

Conservative Overall Majority 73.4%
Conservative Minority 25.8%
Exact Seat Tie Con / Lab 0.3%
Labour Minority 0.6%
Most Seats in Scotland – Labour 62.2%
Most Seats in Scotland – SNP 36.8%
Most Seats in Scotland – Tie 1.0%

I need to do some more work on the Scottish component of the model as I suspect it is over-predicting the SNP share. I will therefore try and get some more data on Scottish polling and see if I can forecast the move from polls to outcome in that area.

3 Comments on “UK General Election Prediction

  1. Two problems with this:

    1. I don’t think extrapolating from
    past experience works for UKIP in this cycle. We’re seeing a genuinely
    new phenomenon here. The Murdoch press and Mail turned on UKIP quite
    some months ago, for example, and it hasn’t impacted on their poll
    ratings at all. They’ve also been riding high in the polls for several
    years. I just can’t see them doing remotely as badly as 4%. I think
    we’re also seeing an early example of the gathering political
    irrelevance of the once feared national press; the readership of daily
    newspapers has collapsed.

    2. I think you’re both too optimistic
    AND too pessimistic on the LibDems. I think in terms of share of the
    vote, again, your model may not hold up. In past election cycles, the
    LibDems got very little coverage between elections and then a sudden
    boost in publicity once rules on proportionate coverage kicked in
    shortly before election day, and their share of the vote traditionally
    followed that. That hasn’t been true over the past cycle and they have a
    record in government to defend. On the other hand, they are much better
    at gaining and, particularly, defending seats than they once were. If
    they got the 16%, most observers belive they’d be looking as 2 or 3
    times the number of seats you’re predicting. I think they’ll be
    massacred in their Labour leaning marginals but might end up holding on
    to a lot of the Tory leaning ones. Eastleigh showed that whatever
    hardcore Labour cyberactivists and journalists think, average Labour
    voters are still prepared to vote tactically.

    Final point – I
    think this is a unique election cycle and might even be the start of the
    breakdown towards a new balance of parties. The UKIP surge, like the
    LibDem boom and bust in 2010, show a huge degree of volatility in the
    electorate; the corrosive anti-politics mood is no secret and
    potentially quite dangerous. It’s also pretty widespread in the West at
    the moment. Predictions are difficult. Remember, some polls have UKIP
    breathing down Labour’s neck to top the poll in the Euros, others have
    the Tories seeing them off comfortably and pushing them into 3rd place.

    who say they’re going to vote UKIP almost universally reckon Farage is a
    plonker, and they don’t care, they just want so shy a coconut at the
    system. You might also be interested in this blog on UKIP I wrote a year
    or so ago after Eastleigh
    and this one about 18 months ago

  2. Um :-).

    Suspect that – for voteshare at least – this is slightly like predicting who will be King of England in 1067 by studying the family tree of Edward the Confessor.

    There are at least two major, and potentially seismic, factors:

    1 – UKIP + LD major changes.
    2 – The Scottish Referendum.

    If the separatists succeed there’s the question of what happens to all the Scottish MPs in 2015; both countries will be weaker, but at least we will not be sharing a country with Salmond.

    • We should expect to see the UKIP poll shares fall as we reach the end of the year (and correspondingly the Lib Dem ratings rise). If that doesn’t happen then at that point we are looking at the new paradigm you are suggesting.

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