About and FAQ


Forecast UK is private project, started in 2008, to predict UK elections. Using a variety of statistical methods we try to provide point in time and future projection forecasts for UK General Elections and other national votes.

What is a Point in Time Forecast?

A Point in Time Forecast is a prediction based on the event happening at the moment of the forecast. A Point in Time Forecast will typically be based on recent opinion polling.

What is an Election Day / Forward Looking Forecast?

An Election Day Forecast is a prediction for the actual result of the election being analysed. An Election Day Forecast will typically be based on recent opinion poll trends, a statistical analysis of previous elections and movement in support before election day, and market expectations of the actual result.

Methodology

Our General Election forecasts take into account historically evidenced movements in party support in the run up to a General Election. This means that we can predict more accurately where we believe support will move between the date of the forecast and the actual election.

We assess all recent opinion polls, a bespoke sample of recent local election results (using data to analyse how local election results in the 12 months before a General Election can help predict the final result) and other barometers of sentiment as to the what the final result will be.

We run a monte carlo simulation of the election taking into account statistical analysis of the variance in support of parties. This helps us create a confidence interval for the actual final result, enabling us to report a “middle point” forecast and a band of possible outcomes.

Why do your forecasts talk about “an X% chance of Y occurring”?

We try to use sophisticated mathematical tools to analyse not just the actual result but the chances of a range of results occurring. We can then use these statistical observations to run thousands of simulations of the election which allows us to identify how likely a particular event is to occur. This is know as the Monte Carlo Method but despite its name has very little to do with gambling.

Have you used these methods before / predicted other elections?

Yes. Most recently we predicted the exact number of Conservative seats in the 2010 UK General Election, and out-performed all the UK polling firms on predicting the result of the 2014 European Election in the UK.

Predictor Con Lab LD UKIP Greens Abs Diff
Actual Result 23.94 25.40 6.87 27.50 7.87
Forecast UK 22.1 26.4 7.8 29.9 7.0 7.04
YouGov 22 26 9 32 10 7.3
ICM 26 29 8 30 6 10.16
Opinium 21 25 6 27 6 10.58
ComRes 20 27 7 25 6 13.04
Survation 23 27 9 33 4 13.04