YouGov independence polling

You may have seen that there are polling numbers from YouGov that purport to show a sudden and statistically significant drop in support for independence - down from 49% to 44%. Now, the first thing to say (and any serious analyst of any political complexion will tell you the same) is that we need to exercise a touch of scepticism about a single poll that shows a big and unexpected change. All polls have a margin of error, but statistically it's inevitable that a small proportion of polls will fall outside the margin of error - ie. they'll be rogue polls. It's possible that's what's happened here. Another possibility is that there may have been a genuine drop in support but that YouGov are overstating it due to the normal margin of error - a reported Yes vote of 44% could mean that the true figure is as high as 46% or 47%.

But of course a third possibility is that the poll is accurate. If so, it's surprising, because two previous Scottish polls during this campaign showed support for independence holding steady at a historically high level. The Ipsos-Mori poll conducted between the 19th and 25th of November showed a 50-50 Yes-No split, so if something has changed it's happened very rapidly. But that's not totally inconceivable, and there are precedents for this sort of thing happening in previous UK-wide campaigns. Remember that the media coverage of general elections compels voters to view political issues through a Britain-wide lens - they're bombarded with political parties making pie in the sky promises to transform Britain for the better. If and when Boris Johnson is returned with a working majority and gets on with delivering a Hard Brexit, that effect is likely to wear off pretty rapidly.

The other factor is that, during general election campaigns, media discussion of independence is heavily slanted in favour of unionist spokespeople. Scottish coverage generally sees the SNP outnumbered 3-1, and at UK level the ratio is probably more like 8-1 or higher - indeed it's not unusual for independence to be discussed without any pro-independence voice being present at all, as happened in last night's rigged BBC leaders' debate. It's the polar opposite of what happens in a referendum campaign, where there has to be parity between both sides. So if the (relative) balance of an indyref campaign causes Yes support to rise, as it did in 2014, it's not unreasonable to suppose that the hopeless imbalance of a general election campaign might cause Yes support to fall, and that any such fall may be only temporary.

Bear in mind that even if this is a genuine drop, it's not as if the floor has caved in - it just takes us back to where we were a year or so ago, before the big Yes surge. Until recently YouGov's normal range for Yes was 43-45%, so 44% is bang in the middle of that. I'm not too concerned about it unless there's a corresponding drop in SNP support.  There's contradictory information about what the fieldwork dates for this poll were - one article seems to suggest it's the same poll that showed the SNP with a huge 16-point lead over the Tories, and if that's true there'd be nothing much to worry about.  However, Britain Elects are saying the fieldwork dates were the 3rd to the 6th of this month, which would mean that it's a different and newer poll, and there might still be a risk of an SNP decline.  We may find out more tonight, because there's usually a flurry of polls on the final Saturday night of a campaign (although whether any of them will be Scottish polls remains to be seen).

*  *  *

I have three new constituency previews in today's edition of The National - this time it's Edinburgh North & Leith, Dunfermline & West Fife and West Dunbartonshire