A number of folks here have drawn out attention to a recent article at the Guardian in which one is told about
a widening disparity between phone and Internet polling, with one producing a 10-point lead for remain and the second reporting that the leave campaign is ahead by four.
What to make of this? One possibility is that both of these polls are outliers. An unweighted average of polls this month has both “stay” and “leave” at 43%, with “undecided” at 14.3%. That’s close to the April numbers: “stay” = 44.43%, “leave” = “41.71,” “undecided” = 12.38%. The Guardian phone poll has “stay” at 47 and “leave” at 39 (which is an eight-point spread, not a ten-point spread as the quote above says, I must have missed something), and that’s about 1.5 standard deviations from the mean for “stay” and about the same for “leave.” The Internet poll was less out of line with the numbers we see elsewhere, with only “leave” more than a standard deviation away from the mean. I don’t know enough about the merits of phone vs. Internet polling to have an informed opinion, but my best guess is that we don’t yet have enough experience with Internet polling to speak to its accuracy in any reliable way. Maybe I’m too pessimistic; who knows?
So that was something of a dead end, I think. But another way to try to get traction on the Brexit question is to look at party membership. The same Guardian piece gives us the following breakdown of UK party membership:
- UKIP: 13%
- Torries: 36%
- LibDems: 7%
- Labourites: 34%
- ScotNats (SNP): 5%
- Greens: 4%
- Other: 1%
Let’s assume – why not? – that voters turn out for the referendum in numbers proportional to their party membership. (Will they? Probably not. But it’s not a terrible working assumption.) I’m willing to bet that UKIP is all in for breaking with Brussels, so that 13% for “leave.”
What about the ScotNats? This is a trickier question than I imagined. It might seem like a no-brainer for members of the SNP to vote for an exit to the EU and then follow that up with a second referendum on Scottish membership in the UK. But SNP leadership is painfully aware that (i) losing a second referendum so soon after losing the first would probably cripple the independence movement for a generation (see Quebec) and (ii) the ScotNats might not yet be in a position to win. In fact, some who favor Scottish independence would like to see it be part of the EU! (That’s not as odd as it might sound. Scotland has a long and troubled history with England, but that doesn’t mean the Scots wouldn’t want voluntary shared governance with other European powers.) So there’s no clear reason (that I can see) to think that ScotNats will vote overwhelmingly for Brexit. Indeed, one recent poll suggested that the Scots (who are not the same as members of the SNP, of course) favor remaining in the EU 3-to-1. That gets us up to 15.5%.
The Tories seem deeply divided over Brexit – another anglophone conservative party in jeopardy because of a populist uprising? Take these numbers for whatever they’re worth, but according to one recent poll, “45 per cent of voters said [pro-Brexit Troy Boris] Johnson was “more likely to tell the truth about the EU than [anti-Brexit Tory David] Cameron, while 21 per cent said the opposite”. Boris has, as we know, said some extraordinary things of late:
Napoleon, Hitler, various people tried this out, and it ends tragically. The EU is an attempt to do this by different methods.
For reals, ya’ll. That’s the voice of truth, according to 2 out of 3 Tories. Well, suppose they do break for Brexit in slightly lower numbers – say 3-out-of-5 Tories vote “leave.” That gets “leave” up to 37.1%.
The Greens look like a pretty solid bet to vote “stay,” since EU environmental protection and regulation is bound to be much better than anything you’re likely to get in the UK alone. The same is true, mutatis mutandis, for bankers and their City cronies, who are no friends of the Party of Kermit . Suppose then that the Greens go overwhelming for “stay” but a few vote “leave.” That gets “leave” up to 37.75%.
It’s hard for me to suss out exactly what the LibDems are up to. Some of their leadership has made noises up the increased strain on the NHS if the UK leaves the EU. LibDemster Tim Farron has called pro-Brexit thought leaders “downright pathetic”. Suppose the LibDems go for “stay” in roughly the same numbers as the Tories go for “leave.” That gets “leave” up to 40%.
What about the Laborites? “Nearly two thirds of Labour voters say they are likely to vote to Remain – around six million people,” according to one source. That sounds pretty good until you realize it also means that one third of Labour voters say that they are likely to vote to leave. Even if Jeremy Corbyn is able to step up – no sure thing as he’s rather ambivalent about Brexit  – that still means you’ve got 51% voting “leave.” So…wow…goodbye to all that.
Or not. All that was very back-of-the-envelope. But it’s not crazy. I might have (okay, I’m sure I do have) some of the numbers wrong. It’s been almost a decade since I lived in England, so I don’t exactly have my finger on the pulse of the UK. Still, this seems like a model I can work with, even if I have to modify the numbers a bit. Suggestions?
For now, I’m lowering my forecast for the UK remaining in the EU to 61%.
 The numbers from April and May are taken from https://ig.ft.com/sites/brexit-polling/
 http://www.theguardian.com/commentisfree/2016/jan/14/brexit-golden-opportunity-nicola-sturgeon-nightmare and http://www.theguardian.com/commentisfree/2016/feb/25/brexit-vote-scotland-out-uk-scottish-independence and more recently http://www.thetimes.co.uk/article/snp-cools-on-referendum-after-brexit-0qdt27mg5
 http://www.dailyrecord.co.uk/news/politics/eu-referendum-record-poll-shows-7934908#qlCQwzRlRIzyCYhF.97 and http://www.theweek.co.uk/eu-referendum/65461/eu-referendum-poll-will-scotland-swing-the-vote