Nostalgia night as TNS reverts to being an extreme No-friendly outlier

You might remember that throughout much of the long campaign leading up to the 2014 independence referendum, TNS was one of the group of No-friendly pollsters, before sensationally swinging in the opposite direction just before polling day.  That dramatic reversal survived into the post-referendum period, with a TNS poll in the autumn of 2015 putting Yes in the outright lead.  Now, incomprehensibly, and in total contradiction of the vast bulk of polling evidence from other firms, TNS has returned to its old ways by showing a very large No lead.

Should Scotland be an independent country? (TNS)

Yes 40% (-7)
No 60% (+7)

This is by some distance the worst poll for Yes from any firm since September 2014.  The previous low was Yes 43%, No 57% from YouGov.

The ever-reliable buffoons who insist that "only the last poll we set eyes upon matters" will inevitably lose all sense of perspective over this, but those of us who are a little more level-headed will recognise an indisputable fact here - that this poll can't possibly negate the much more favourable polls we've seen for Yes over the last few days, for the simple reason that it was conducted earlier.  TNS polls are always way out of date by the time that we see them, and this one is no exception - fieldwork started in late March and concluded two weeks ago, which dates it well before the Panelbase and Survation polls.  The majority of interviews also took place before BMG found a virtual 50/50 tie.  So the verdict from those three online pollsters is clear enough - they are more up-to-date, and they do not corroborate the findings of TNS.

That's not to say that if a more recent TNS poll had been conducted, it would necessarily have produced a healthier result for Yes.  TNS traditionally use a distinctive face-to-face data collection method, and that could largely explain why they've suddenly bolted off in a different direction from other firms (assuming this isn't an outright rogue poll, which always has to be considered a possibility when the numbers are this unexpected).  And yet it seems highly unlikely that the new No-friendly trend is going to be seen across all non-online polls, because as recently as early March, a telephone poll from Ipsos-Mori put Yes in a slight outright lead - a better result, ironically, than has been seen in any online poll so far this year.  It's going to take time to make sense of what's happening, because at the moment there's just no comprehensible pattern in any of this.  The BMG, Survation and Ipsos-Mori numbers are simply not reconcilable with TNS - the standard 3% margin of error can't explain such a big divergence.

You would have to say that the balance of probability is that Yes are trailing at the moment, but whether they are trailing by 20% as TNS say, or by 2% as BMG say, or whether the truth is somewhere in between those extremes, is anyone's guess.  We mustn't forget just how absurdly far adrift Leave were in most telephone polls before pulling off victory in the EU referendum last June - so it's perfectly possible that online polls are more accurate these days.

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SCOT GOES POP POLL OF POLLS

Should Scotland be an independent country?

Yes 45.7% (-1.1)
No 54.3% (+1.1)

(The Poll of Polls is based on a rolling average of the most recent poll from each firm that has reported at least once within the last three months. The firms included in the current sample are Panelbase, BMG, Ipsos-Mori, YouGov, TNS and Survation.)