UK 2015 – Forecast – 6th January 2015

This is the latest of our forecasts for the UK General Election in 2015. To see our methodology click here.


Our mid point and confidence interval forecast for seats is as follows.

Party Seats – Mid Point Seats 50% CI Seats 95% CI
Conservatives 310 295 – 321 267 – 338
Labour 275 264 – 287 249 – 307
Liberal Democrats 24 17 – 31 8 – 45
UKIP 1 0 – 3 0 – 10
SNP 16 13 – 19 9 – 29
PC 4 2 – 4 2 – 4
Others inc. Green (GB) 3 2 – 3 0 – 8
Irish 18 n/a n/a

Our mid point and confidence interval forecast for votes (mainland GB) is as follows.

Party Vote% – Mid Point Vote% 50% CI Vote% 95% CI
Conservatives 33.3 32.0 – 34.7 29.7 – 37.2
Labour 29.0 27.8 – 30.2 25.4 – 32.9
Liberal Democrats 16.3 15.2 – 17.4 13.1 – 19.6
UKIP 11.6 10.4 – 12.8 8.2 – 15.3
Green 4.8 3.6 – 6.0 1.2 – 8.5

Our probability of different outcomes is as follows.

Event Probability
Conservative Majority 16.4%
Conservative Minority 68.2%
Exact Tie Labour and Conservative 0.2%
Labour Minority 15.2%
UKIP more votes than Liberal Democrats 2.7%

What are the main points of your forecast?

We identify the following events / features.

  • The Labour position has strengthened slightly in the past month and a half. We still expect their current level of support to fall away before May and the Conservatives’ position to strengthen.
  • Although the Conservative lose seats to Labour, they more than make up for this in gaining seats from the Liberal Democrats. We are exploring improving the Liberal Democrat incumbency effect after analysis which may mitigate some of these losses.
  • The SNP are set to at least double their seats in Scotland. If they maintain their current poll rating up to the General Election (at the moment we are expecting the SNP support to fall back in the next few months) we expect them to even outperform Labour on polling day in Scotland.
    At the moment we are weighting down the current surge in SNP support. From our next forecast we will begin to increase their support as we become more sure of the sustainability of the increase in support.
  • UKIP support (as expected) appears to be declining as the electorate begins to make choices about who they will actually support in May.
  • Wales – We have improved our modelling for Wales and this is reflected in the figures above.

Why is your forecast different to that of Stephen Fisher?

We use the same fundamental forecasting principle as Professor Stephen Fisher with the following crucial differences.

  • We use a different sample of elections to model movement of party support prior to a national vote
  • We specifically model UKIP support and do some additional local analysis on where UKIP might do well
  • We have regional models which help to capture specific local peculiarities (for example, we model Scotland independent of the rest of Great Britain, allowing us to capture the current spike in support for the SNP – Stephen Fisher currently does not do this).
  • We have used some components of this methodology before and that allows us to make corrections as we compare our outcome to real results.

What improvements are you hoping to implement next?

At the moment the model isn’t taking into account polling in individual seats. As such data becomes richer and more consistent we will attempt to use it in our forecast.

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