Ipsos MORI still have a final final poll to come in tomorrow’s Evening Standard, but they also have a Scottish poll out tonight for STV. Topline voting intention figures with changes from their previous Scottish poll, right back at the start of August, are YES 49%(+7), NO 51%(-7). As with the YouGov, TNS and ICM polls they’ve shown a big shift towards YES over the last month and, as with everyone else, they end the campaign with YES and NO extremely close, but NO just an inch ahead. I’ll add tables later on…

Panelbase’s final call poll for the referendum is out and also has a 48/52 split. Full topline figures are YES 45%, NO 50%, Don’t know 5%, which excluding don’t knows becomes YES 48%, NO 52% – the same as in all three of yesterday’s polls. While it doesn’t seem to be their “official” headline figure, Panelbase also included a forced choice question to don’t knows asking them to imagine they were in the polling station, right now, with no don’t know option – with that data it would have been YES 47, NO 53. Full tabs are here.

Still to come later tonight are the final YouGov poll and the penultimate Ipsos MORI poll.


Two days to go until the referendum, and we starting to get the final “eve-of-election” polls. Three of them should be out tonight – ICM’s final poll for the Scotsman, Opinium’s final poll for the Telegraph and a Survation poll for the Daily Mail. As at the weekend, I’ll update this post as they come in.

ICM’s poll for the Scotsman shows YES on 41%, NO on 45%, don’t knows on 14%. Excluding don’t knows that works out at YES 48%, NO 52%. Last week ICM did two Scottish polls – a traditional telephone one for the Guardian which showed a two point lead for NO, and a rather unusual online one for the Sunday Telegraph showing an eight point lead for YES – far and away their best showing in any poll. However, the ICM online poll had a small sample size and seemed to be a Scottish boost to a GB poll rather than a bespoke poll in its own right, so we were a bit dubious about it. Today’s poll suggests we were right to be sceptical – a bespoke, full size ICM online poll is bang in line with the rest of the pack.

UPDATE: Almost as soon as I’d posted Opinium’s Telegraph poll also appeared, with identical headline figures of YES 48%, NO 52%. This is almost the same as their poll for the Observer at the weekend which had a 47/53 split. Tabs for the Opinium poll are online here (I don’t think the ICM ones will be up until the morning).
Survation is the final confirmed poll of the night, and I’m expecting that at 10pm.

UPDATE2: And Survation are also showing YES 48%, NO 52%. Tabs are here. Once again, it very similar to their previous poll which was showing 47/53. Three polls tonight, and all three showing a 48/52 split. The referendum polls really have come into a very tight consensus now, updating my list from the weekend we now have levels of YES support (excluding don’t knows) of:

Panelbase (online) 49%
ICM (phone) 49%
TNS (face to face) 49%
YouGov (online) 48%
ICM (online) 48%
Opinium (online) 48%
Survation (online) 48%
Survation (phone) 46%

The final polls tomorrow (and for MORI Thursday morning) may pick up very late swing, but barring any surprises it looks like the polls are going to be predicting a narrow victory for NO.

The Scottish polls at the end of last week and the weekend were broadly clustered around a small No lead. There are a couple of days campaigning left, but perhaps a more likely route to a YES victory is if the polls are underestimating the level of YES support for some reason. Over the last couple of days I’ve seen several blogs or articles pondering whether the polls could be wrong, could they be underestimating YES or NO?

It would be hubris to suggest the polls couldn’t be wrong. Obviously they can. At most elections there are polls that perform better or worse than their peers, some of that is better methodology. When the polls are close most is probably just normal sample variation. That’s a matter for another time though, here I’m pondering more about the possibly that all the polls are wrong, the potential for a systemic bias with everyone a bit too yes or a bit too no. This is possible too – think of the way all polls overestimated Lib Dem support in 2010, or most famously how all the polls overestimated Labour support in 1992. How likely is that?

The Scottish referendum is a bigger challenge for pollsters than an election would be because it’s a one-off. In designing methodology for voting intention the experience of what worked or didn’t work at previous elections weighs heavy, and most companies’ weighting schemes rely heavily upon the previous election – if not directly through weighting by recalled vote, in using the data from the previous election in designing and testing other weighting targets. For a referendum you can’t take that direct approach, pollsters needed to rely more on modelling what they think is an accurate picture of the Scottish electorate and hoping it reflects the Scottish people well enough that it will also reflect their referendum voting intentions – it’s complicated because Scotland has a complicated electorate. Scottish voters have two Holyrood votes and a Westminster vote, and they use them all in different ways with different political loyalties. Within the space of a year Scotland managed to be a Labour stronghold at Westminster and to produce a SNP landside at Holyrood – using either election alone for weighting gives a rather different picture of what the Scottish electorate are like, even though you are trying to model the same population. Different companies have arrived at different methods of political weighting to deal with the issue – Survation, ICM and TNS weight by Holyrood recalled voted alone, YouGov weight by Holyrood recalled vote with a nod towards 2011 Holyrood voters who backed Labour in 2010, Opinium weight by Holyrood and Westminster recalled vote, Panelbase weight by Holyrood and European recalled vote, Ipsos MORI don’t use political weighting at all. Despite the variance they have all converged to produce the same sort of result, and that gives me some confidence – if there was a particular skew from being online or from using Holyrood recalled vote we would expect to see different results.

Most speculation about whether the polls might be wrong has – rightly in my view – concentrated on two particular issues. Very high turnout and differential response rate.

Polls aren’t very good at predicting an actual percentage for turnout – people overestimate their likelihood to vote, and the actual turnout figures they are compared to are a bit ropey because of inaccuracy and incompleteness of electoral registers – that aside, they are pretty good at predicting relative turnout, and the referendum looks set to have a much higher turnout than any recent election. This poses a problem. Any professionally run opinion poll will make every effort to get as representative a sample as possible, but in practice there are limitations. People on the very fringes of society, people struggling in absolute poverty, those utterly detached from mainstream politics and civic society – people on the extreme edge are probably underrepresented in opinion polls of all sorts. In most voting intention polls this doesn’t matter, as people on the very fringes are also extremely unlikely to vote… but if the Scottish referendum does manage to engage some who were previously totally detached and, crucially, those people vote in a substantially different way to other people of similarly marginal demographics, then it could be a source of error.

The second potential pitfall is differential response. Much of the media discussion around this has called it “shy Noes” – people who want to vote no but are reluctant to admit it to pollsters. That’s possible, but it should be much less of a problem with online polls when people are giving their opinion to an impersonal computer screen. I think there’s more risk from the other side of the same coin – “enthusiastic yesses”. It is very clear from activity online and reported campaigning activity that YES supporters are more enthusiastic, what if that is also reflected in responses to opinion polls? What if the yes supporter, full of zeal and keen to share their view, happily agrees to do the phone interview while the less enthused No supporter doen’t want to interupt their tea? Eagerly clicks on the email when the No voter doesn’t bother? Issues of differential response can be mitigated through careful sampling and political weighting but again, it can only go so far. Pollsters can make sure they aren’t getting too many people who voted SNP in 2011, but there’s not much they can do to be 100% certain they are aren’t, for example, getting too many Yes voting Labour voters and not enough No voting ones.

So, how confident am I about the polling in the Scottish referendum? Well, I suppose I’m fairly confident – if there was anything I thought we were doing critically wrong we’d have corrected it. If I had to put money on the result, I’d certainly back the polls, but the potentials for error are there. We’ll know on Friday if they’ve been avoided.

As well as the Ashcroft and Populus polls earlier today we also have the monthly ICM poll for the Guardian tonight, reported here. Topline figures with changes from a month ago are CON 33%(+2), LAB 35%(-3), LDEM 10%(-2), UKIP 9%(-1), GRN 7%(+3). It shows a sharp narrowing of the Labour lead, but it’s almost certainly a reversion to the mean: the previous ICM poll had the Labour lead jumping up to 7 points when it had been previously showing Labour and the Conservatives pretty much neck and neck.

The poll also asked about English and Welsh attitudes to the Scottish referendum and to further devolution. As we’ve seen elsewhere, there is little support for a currency union with an independent Scotland amongst the rest of the UK – 27% of people say the remainder of the UK should negotiate a currency union, 63% they should not. Asked about more devolution in England, via regional assemblies or an English Parliament 45% think it would help their area of England, 42% that it would not.