Category Archives: EU referendum

A combined forecast for the UK’s EU membership referendum

Stephen Fisher and Rosalind Shorrocks

There is a lot of evidence from the academic research on forecasting that suggests it is a good idea to combine information from different sources (e.g. here). In US and German elections generating a forecast by combining the forecasts of others has a good track record. For the upcoming US presidential election pollyvote.org provides an average of different forecasts together with excellent summaries and discussions of the different methods and forecasts.

We have developed a similar method of combining forecasts for the UK’s referendum on EU membership on 23rd June 2016. The summaries of the average forecast win-probability and share of the vote for Remain by method and then overall are presented in the tables below. Note that there are different components for each because some of the source forecasts provide only probabilities or only vote share.

Share of the vote Remain Leave
Combined forecast (mean) 53.6 46.4
Betting markets 53.9 46.1
Polls 51.4 48.6
Expert forecasts 56.0 44.0
Volunteer forecasts 54.6 45.5
Poll based models 54.0 46.0
Non-poll based models 52.0 48.0
Probability that Remain wins
Combined forecast (mean) 66.8
Citizen forecasts 64.3
Volunteer forecasts 71.2
Prediction markets 65.4
Betting markets 62.2
Polls 63.0
Poll based models 74.7

Continue reading A combined forecast for the UK’s EU membership referendum

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Second forecast for the Brexit referendum

by Stephen Fisher and Alan Renwick

A month ago we issued our first forecast for the EU membership referendum on 23rd June 2016. Based on an analysis of referendums in the UK and on the EU outside the UK, and on vote intention opinion polls we forecast that Remain had an 87% chance of winning, and that Remain would get 58% of the vote, plus or minus 14. This was in part based on our polling average (excluding Don’t Knows) of 55% for Remain on 11th March.

Our current forecast suggests the contest is a fair bit closer. Our polling average now puts Remain on 52%. We now give Remain a 73% chance of winning and estimate that the Remain share of the vote will be 54% plus or minus 13 points.

The key change here is the drop from 55% to 52% Remain in the polling average. The main reasons for this are as much or more methodological than substantive. Continue reading Second forecast for the Brexit referendum

First Forecast for the Brexit Referendum

By Stephen Fisher and Alan Renwick

The UK will have a referendum on whether to remain in or leave the EU on 23rd June 2016. We have developed a method for forecasting the outcome based on current vote intention polls and analysis of opinion polls from previous referendums from the UK and across the world. Continue reading First Forecast for the Brexit Referendum