The morning after the night before

So how did the polls do at predicting the general election result? Well, it certainly wasn’t a disaster. On the whole, the final polls got the Conservative and Labour votes right, but overestimated support for the Lib Dems and underestimated the smaller parties.

At the time of writing, with 641 of 650 seats declared, the Conservatives are on 36%, Labour are on 29%, the Lib Dems are on 23% and the rest are on 12% (excluding Northern Ireland, as the opinion poll samples do, the figures are 37%, 30%, 23% and 10%). Results from the final polls are listed below – all of them had the Tory vote between 35% and 37% and most had Labour on 28% or 29%. But almost all of them overstated Lib Dem support, placing the party either just behind Labour or neck-and-neck.

It was always going to be tough for the pollsters to work out how the Lib Dems’ dramatic surge in the polls after the first TV debate would translate into votes.

Angus Reid Public Opinion’s final poll, published on Wednesday, was the furthest out in its predictions for the second two parties, putting the Lib Dems in second place on 29% and Labour on just 24%. However, it did produce a closer prediction of support for the smaller parties than some of the others.

Many pollsters had hinted at the ‘softness’ of Lib Dem support, but apparently didn’t attach sufficient importance to this into their predictions.

Research spoke this morning to Ben Page of Ipsos Mori, who was reluctant to get into too much detail before all the votes had been counted, but said that the research industry had been “vindicated” over earlier criticism of the exit polls. “Iain Dale, the prominent blogger, said he would run naked down Whitehall if the exit poll was right and the exit poll was right,” said Page. “So the market research industry is looking forward to seeing Iain Dale naked in Whitehall some time soon.”

As for the apparent overstatement of Lib Dem support, Page said: “On our final poll for the Evening Standard on Wednesday, we had 40% of Lib Dems saying they might change their mind. We’ll all want to look and see what we can do about soft support for the Lib Dems, we’ll have to find a rational and reasonable way of dealing with it rather than just saying Lib Dems tend to overstate. We will all be looking at certainty of vote, voting history – the surge was partly younger people – and late switching, things like that. The Lib Dems were most likely to say they would vote tactically. So the support was there but it didn’t actually manifest itself in votes on the day – Lib Dem support was slowly deflating after initial Clegstacy and on the day fell further.”

Pollsters can only do so much, Page said, especially as political polling represents only a tiny part of the business of most of the companies that do it (even if it accounts for most of their publicity). If the industry really wanted to, he said, they could follow the lead of the broadcasters with the exit polls and work together. “We could all combine together our resources and do a final, final poll that would be about as perfect as we could make it,” he said. “Whether we’ll ever do that I don’t know.”

ICM, which also did its surveys by phone, seems to have come closest to the Lib Dem share of vote with its estimate of 26%, but was still 3% out. Research director Martin Boon said it was a disappointing night for the polling industry in general. “There are some sizeable average errors out there and we all do need to take a look at our methods,” he told Research. “Clearly all polling companies have overstated the Lib Dems, so there has to be something consistent going on. It would be a little bit premature to consider the reasons for this but it’s up to the opinion pollsters to see why it might have been the case. We’re always testing our methods and this is the best time to be looking at methodologies, assumptions and techniques in order to improve them in the future.”

But considering the number of wild card factors involved in this election, and the anxiety in the MR industry about a repeat of the polling failures of 1992, it could have been a lot worse.

The final poll results were as follows:

These polls were, of course, all conducted in different ways and at different times, so please visit the sites of Angus Reid Public Opinion, ComRes, Harris Interactive, ICM, Ipsos Mori, Populus, YouGov and the BBC if you want more detail.

UPDATE 16:25, 7/5/10 It has been brought to our attention that, as opinion poll samples exclude Northern Ireland, we should state share of vote figures excluding NI, which are: Conservatives 37%, Labour 30%, Lib Dems 23%, the rest 10%.