All posts by electionsetc

EU referendum, Methodology

How the BBC will be benchmarking the results on EU referendum night

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by John Curtice and Stephen Fisher.

Referendum night is going to represent something of a departure from usual. There will not be the drama of an exit poll announcement to stir excitement – and possibly shock – at 10pm. Meanwhile, when the actual results do start to be announced, except in Northern Ireland they will not be declared by the parliamentary constituencies with which we have all become familiar. Rather they will be unveiled local authority by local authority. As a result, we will get just one declaration for the whole of Birmingham, while, at the other end of the spectrum, the Isles of Scilly will get their moment in the sun.

But perhaps the biggest departure from the routine of election night will be that there will be no ‘last time’ against which to compare the results as they are declared. So when Sunderland or Swindon announce their result we will not be able to say whether it represents a ‘swing’ to Remain or Leave – and thus for which side, if either, it represents a good result.

To overcome this problem we have, on behalf of the BBC, been beavering away at establishing which local authorities appear to be more likely to record a relatively strong vote for Remain, which are the ones where Leave can be expected to do relatively well, and which are the council areas where the two sides could be expected to be equally matched. Our evidence has come primarily from a dataset of over 61,000 interviews about people’s attitudes towards the EU. These interviews were conducted with people in Great Britain by YouGov between March of last year and March of this year and we are deeply grateful to the company for making these data available.

Continue reading How the BBC will be benchmarking the results on EU referendum night →

EU referendum

Do people tend to vote against change in referendums?

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by Stephen Fisher and Alan Renwick.

It is commonly asserted by people commenting on the EU referendum that people tend to be risk averse and so vote against change. The Prime Minister appealed to people not to “roll the dice” on their children’s and grandchildren’s future. Daniel Hannan in his book Why Vote Leave accepted the idea of risk aversion in referendums, and then argued that people should see remaining in the EU as more risky than leaving.

But is it really true that people tend to vote against change in referendums? There are certainly several examples in Britain where people have rejected change, the most prominent examples include the referendums on Scottish Independence, the Alternative Vote electoral system, and, in 1975, the UK’s membership of the European Community. But it is also true that people in different parts of Britain have voted for change in referendums on numerous occasions. They voted for a Scottish Parliament (and separately to give it tax varying powers), a Welsh Assembly (and later for it to have more power), a Greater London Assembly, and the Good Friday Agreement. Setting aside referendums at the sub-regional level, the change option has won in six out of the thirteen referendums that have been held in the UK.

It maybe objected that both of the UK wide referendum results have been for the status-quo. True. So what if we cast our net further afield?

Continue reading Do people tend to vote against change in referendums? →

EU referendum

What is going on in the EU referendum? Some comments based on opinion poll evidence

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by Stephen Fisher.

The prominent Leave campaigners are at pains to point out how much they love Europe. Boris Johnston says he is a proud European. Leavers claim to love Europe but hate the EU.

Meanwhile leading figures in the Remain camp dare not admit to any fondness for either Europe or the EU. Their eurosceptic tone emphasises UK membership as a marriage of convenience, to be justified by considerations of UK interests alone. This makes plenty of sense as a pitch to a population that overwhelmingly dislikes the institutions of the EU and who identify with Britain or one of the home nations much more than they think of themselves as European.

For the large majority of people in the UK pretty much the only substantial reason for voting Remain is economic. “Project Fear” is not only the obvious strategy for the Remain campaign, it is pretty much the only possible one that could secure them victory. The main reason why the polls are suggesting the outcome of this referendum will be close is that the public are not yet convinced the economy will suffer, and in particular that they personally would be worse off, if we left.

Continue reading What is going on in the EU referendum? Some comments based on opinion poll evidence →

EU referendum, Forecast updates, Historical & polls based forecast

Forecast update for the Historical Referendums and Polls based method

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by Stephen Fisher and Alan Renwick.

We offer our condolences to the family and friends of Jo Cox MP. We hope that it is not disrespectful of us to post this updated forecast now that the official campaigns have resumed.

Our polling average now has Remain at 49% after setting aside Don’t Knows.

From this we forecast Remain to get 50% of the vote.

The 95% prediction interval is only a little narrower than ±12 points. So Remain are forecast to win between 39% and 62% of the vote.

The probability that Remain will win the referendum is now 52%.

The methods behind our forecast

The method behind this forecast is based on the historical experience of referendum polls and referendum outcomes in the UK and on the EU elsewhere, as discussed here.

Our polling average is constructed by taking the most recent poll from each company within the last two weeks. If a company uses both phone and online modes then both the most recent phone poll and most recent online poll are used. This applies to BMG, ICM and ORB this week. The current average is based on the results of twelve polls from nine companies, of which six were conducted by phone and six online. All polls are adjusted to account for the tendency for phone polls to be more favourable to Remain. This is done by adding 1.75 to the Remain share for online polls and subtracting the same amount for phone polls.

EU referendum, Forecast updates, Historical & polls based forecast

A 50:50 forecast from the Historical Referendums and Polls based method

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by Stephen Fisher and Alan Renwick.

Our forecast has taken a dramatic turn. Last week our polling average had Remain at 51% after setting aside Don’t Knows. It has this week dropped a further two points to 49%. This means Leave is ahead in our polling average for the first time, with 51%.

The forecast share of the vote for Remain has correspondingly dropped from 53% to slightly over 50%.

The 95% prediction interval is still ±12 points. So we are now forecasting that both Leave and Remain will win between 38% and 62% of the vote.

The probability that Remain will win the referendum has fallen from 68% last week to just 51% this week. Continue reading A 50:50 forecast from the Historical Referendums and Polls based method →

EU referendum, Forecast updates, Historical & polls based forecast

Historical Referendums and Polls based Forecast Update

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by Stephen Fisher and Alan Renwick.

Remain have continued their gentle slide in the polls. Last week our polling average saw Remain drop from 53% to 52%. Now they are on 51% after setting aside Don’t Knows.

The further one-point drop in our polling average has produced a one-point drop in the forecast share of the vote for Remain, from 54% to 53%.

The 95% prediction interval is still ±12 points. We are now forecasting that Remain will win between 40% and 65% of the vote.

The probability that Remain will win the referendum is now down to 68%.

The method behind this forecast is based on the historical experience of referendum polls and referendum outcomes in the UK and on the EU elsewhere, as discussed here.

Our polling average is constructed by taking the most recent poll from each company within the last two weeks. If a company uses both phone and online modes then both the most recent phone poll and most recent online poll are used. This applies just to ICM this week. The current average is based on the results of eight polls from seven companies, of which three were conducted by phone and five online. All polls are adjusted to account for the tendency for phone polls to be more favourable to Remain. This is done by adding 2.2 to the Remain share for online polls and subtracting the same amount for phone polls.

EU referendum, Forecast updates, Historical & polls based forecast

Forecast update for the Historical Referendums and Polls based Method

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by Stephen Fisher and Alan Renwick.

The small shift towards Remain in the polls that we observed last week has been reversed. Setting aside Don’t Knows, our polling average for Remain has dropped back from 53% to 52%. Despite there being little difference between the headline figures for yesterday’s ICM phone and online polls, our estimate (and corresponding adjustment) for the typical difference between the two modes of interviewing has barely changed.

The one-point drop in our polling average has led to a corresponding one-point drop in the forecast share of the vote for Remain, from 55% to 54%. The 95% prediction interval surrounding this estimate has again narrowed very slightly to ±12 points. So we are now forecasting that Remain will win between 42% and 66% of the vote.

Overall the probability that the Remain vote will be larger than the Leave vote has dropped from 79% last week to 73% now. Continue reading Forecast update for the Historical Referendums and Polls based Method →

EU referendum, Referendums

How good are referendum polls in the UK?

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by Stephen Fisher and Alan Renwick

As online and telephone polls for the EU referendum continue to tell different stories about the contest, there is increasing debate about the relative merits of each method (e.g. here, here and here). Much of this debate is focused on which of the two modes is more accurate. Does Remain have a comfortable lead, as phone polls suggest, or is it too close to call, as the online polls indicate? Continue reading How good are referendum polls in the UK? →

EU referendum, Forecast updates, Historical & polls based forecast

The Historical Referendums and Polls based forecast, one month out

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by Stephen Fisher and Alan Renwick.

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% on 10th May to 53% 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% of the vote in a month’s time. The 95% prediction interval surrounding this estimate has narrowed very slightly to ±12.5 points. So we are forecasting that Remain will win between 43% and 68% 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%, up from 72% two weeks ago.

EU referendum, Forecast updates, Historical & polls based forecast

An Update on the Historical Referendums and Polls based Forecast

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by Stephen Fisher and Alan Renwick.

We have published two previous forecasts of the result of the UK’s referendum on EU membership, which are based on current vote intention opinion polls for this referendum and on the historical experience of referendum polls and referendum outcomes in the UK and on the EU elsewhere. The main ideas behind this approach are set out here. This post offers an update. Continue reading An Update on the Historical Referendums and Polls based Forecast →