From Professor Curtice;
http://blog.whatscotlandthinks.org/2014/02/survation-enter-the-fray/
"Survation, the regular (internet) pollsters for the London newsdesk of the Mail on Sunday (though not of the desk in Scotland), have entered the referendum polling fray for the first time this weekend.
They put the Yes vote at 32%, No at 52%, with 16% saying Don’t Know (after taking into account people’s reported likelihood of voting). Once the Don’t Knows are excluded, that means Yes are on 38%, No on 62% – almost exactly in line with the average reading of the six polls conducted since the publication of the Scottish Government’s White Paper in November. Of course, as Survation have not previously conducted a poll on referendum vote intentions, we do not know whether or not the poll is further confirmation that there has been a swing to Yes.
However, there is one feature of the way in which this poll has been reported that should be noted. As previous polls that have asked people how they voted in both the 2010 Westminster and the 2011 Holyrood elections have discovered, people’s memories of what they did on the latter occasion seem to be more accurate than their recollection of what they did in 2010. Certainly, when unweighted this poll has a 45% SNP vote in 2011, with Labour on 29% – in other words more or less exactly in line with the actual result. In contrast the unweighted figures for how people said they voted in 2010 are 42% SNP, 32% Labour, which is far from the actual result. It is because of findings such as these that all those pollsters who weight their referendum poll samples by past vote have opted to do so by how people said they voted in 2011 rather than in 2010.
This poll has, however, been weighted according to how people said they voted in 2010. The effect, predictably, has been to increase the estimated No lead considerably. Before the data were weighted at all (including to make sure that the sample matches the demographic profile of Scotland), the Yes tally stood as high as 43% (after the Don’t Knows are excluded). The weighting has knocked as much as five points off that figure. It looks highly likely that if Survation had followed the same practice as most other pollsters, the reported Yes vote in this poll would have been over 40% – just as it was in last weekend’s ICM poll and is in this weekend’s TNS BMRB poll...."