Stephen Fisher and Alan Renwick have developed a method for forecasting the outcome of the EU referendum based on current vote intention polling and analysis of opinion polling from previous referendums in the UK and across Europe. Since the last update two weeks ago the probability of a Remain win has increased from 72 per cent to 79 per cent.
There has been a small shift towards Remain in the polls over the last two weeks. Excluding don’t knows, our polling average for Remain has moved from 52 per cent on 10th May to 53 per cent now. This figure is based on the most recent polls from each of seven companies: one from each but two from ICM (one by phone and one conducted online). The Remain share has been adjusted down by 2.15 points for telephone polls and up by the same amount for online polls to account for the relatively stable gap between these different methods in the levels of support they tend to give the two sides.
Using the historical experience of referendum polls and referendum outcomes in the UK and on the EU elsewhere, as discussed here, our latest forecast is for Remain to win 55 per cent of the vote in a month’s time. The 95 per cent prediction interval surrounding this estimate has narrowed very slightly to ±12.5 points. So we are forecasting that Remain will win between 43 per cent and 68 per cent of the vote.
Values closer to the middle of this range are more likely. Overall the probability that the Remain vote will be larger than the Leave vote is now 79 per cent, up from 72 per cent two weeks ago.
About the authors
Dr Stephen Fisher is an Associate Professor in Political Sociology and the Fellow and Tutor in Politics at Trinity College, Oxford.
Dr Alan Renwick is the Deputy Director of the Constitution Unit.