No evidence of a late swing – analysing our re-contact survey

No evidence of a late swing – analysing our re-contact survey

This would at the same time be the most comforting and unnerving explanation for pollsters because it would imply that our methods were as accurate as it is possible for polling to be but still proved incapable of predicting the result correctly.

On Election Day itself we sent a survey out to everybody who said they were likely to vote in a recent poll and asked them to fill it out only once they had voted.

Around four and a half thousand people answered this, only a fifth of the official exit poll but significant nonetheless, and if there had been a substantial late swing to the Conservatives then we should have seen some of it here.

The results below show the raw figures and then with each layer of weighting added to make them comparable to our final voting intention poll. That poll, if you remember, showed the Conservatives on 35% and Labour on 34%.

Election day re-contact survey Raw figures Weighted to match final poll demographics of likely voters With demographic and party propensity weighting
Conservative 33% 32% 33%
Labour 32% 32% 33%
UKIP 15% 15% 12%
Liberal Democrats 9% 8% 9%
SNP 5% 5% 4%
Green 5% 5% 6%

As we can see, all this gave us was the same dead heat or tiny Tory lead. The Labour figure was slightly more accurate but this again underestimated the Conservatives while overestimating UKIP and the Greens.

The percentage of those who said they would vote Conservative who followed through on that was 91%, identical to the Labour figure while those for the Lib Dems, UKIP, SNP and Greens were 83%, 88%, 98% and 82% respectively.

We therefore feel confident in saying that there is no evidence of a late swing to the Conservatives among our voting intention sample and therefore we cannot claim that our pre-election poll was largely correct but rendered inaccurate by a late swing.

The people in our sample did not change their votes on the day itself in anything like sufficient numbers to explain the final result so we must instead look to who we asked and how we counted them.