YouGov admits 'we got it wrong, gov'

As I've mentioned in previous posts, one of the most diverting spectator sports over the last few weeks (it even marginally beats the curling, seeing as we haven't been winning) has been keeping up with the increasingly fantastical array of theories that panic-stricken CyberTories have dreamt up in an attempt to explain away the reality that their party's once-impregnable YouGov poll lead has pretty much receded to nothing. No wonder YouGov have just given their website a dodgy makeover - the old version must have been creaking under the weight of all the rather tired and emotional number-crunchers who had turned up, desperate to spot The Killer Flaw. With truly delicious irony, their efforts have finally coaxed an official response out of YouGov's chairman Peter Kellner, in which he refreshingly concedes that a mistake has indeed been made with the weightings - but that the party whose support has been underestimated is not the Tories, but the SNP! Kellner candidly spells out the precise extent of the blunder -

"These [new weightings] will typically reduce Labour’s recorded share of support in Scotland by two-to-three percentages points and increase the SNP’s recorded share by a similar amount."

In other words, Labour's lead over the SNP has been regularly overstated by a whopping four to six percentage points in YouGov polls. This doesn't entirely clear up the mystery of the disparity between the Scottish findings of YouGov and Ipsos-Mori, but it certainly narrows what had previously been a yawning chasm between the two.

Perhaps the only disingenuous part of Kellner's statement is when he suggests that the discovery of the mistake doesn't really materially alter the 'big picture' of the Scottish political scene. I beg to differ. Only a man who reckons that 'only Westminster matters' could possibly make such a statement, because (unless I'm missing something) Labour's recent five-point YouGov lead in Holyrood voting intentions has essentially just been shown to be a mirage. But even on the issue of Westminster voting intentions, a great many overblown 'big picture' claims were being made on the back of YouGov's recent flawed Scottish polls, most notably that the Tories may be on the cusp of overtaking the SNP in the battle for second place at the general election. That prospect now, at a stroke, looks considerably more distant. As an illustration, here is YouGov's latest Scottish poll/subsample aggregate for the Sun (covering Westminster voting intention only), with the figures reweighted under the new system -

Labour 39%
SNP 26%
Conservatives 18%
Liberal Democrats 12%
Others 6%

Now, those numbers could of course be better still, but doesn't that look a lot healthier for the Nats?