Alastair Meeks on the importance of the London, Scottish & Welsh surveys

The 2015 general election was a disaster for the polling companies. On the eve of the election, all the pollsters were predicting a hung Parliament with the Conservatives and Labour neck and neck. In the event, the Conservatives were 6% ahead of Labour and got an overall majority.

Since then, the pollsters have flagellated themselves, put on hair shirts and sought to uncover what exactly went wrong. They have conducted investigations, issued reports and held symposia on the subject. They have put in place corrective measures. But we don’t yet know whether the time for remorse is over. There remains a gnawing anxiety that the pollsters might still be getting it wrong.

The general election was not an isolated failure. The Scottish independence referendum polling was fairly uniformly 3% off, the same margin as the standard general election error. This wasn’t much noted at the time but if the error had been 3% the other way from the published polls, Scotland would now be independent. In a close referendum, accuracy to plus or minus 3% is not much use.

The EU referendum betting reflects that. The betting markets are apparently moving independently of any polling. Opinion polls are being treated as having junk status. This seems excessive. We can at least expect them to be giving us a sense of which way opinion is moving, even if their absolute accuracy is suspect.

In any case, we have an upcoming opportunity to calibrate their accuracy. The 5 May round of elections will allow us to see the accuracy of polling in Scotland, Wales and London on those elections. There has been plenty of polling of all three of these elections. So watch them carefully: they will be invaluable in helping us determine how effectively the pollsters have got to grips with their problems.

If the polls perform reasonably well against the actual outcome, take note. So if Mayor Khan has won a comfortable victory, Labour are left running a minority government against a Plaid Cymru opposition and the SNP increase their overall majority, perhaps it’s time to start taking the polls a bit more seriously again when placing your bets. After all, it would be a shame to be completely discounting a potential source of information, wouldn’t it?

Alastair Meeks