Lord Ashcroft has likened the current state of the polling industry with that of the Liberal Democrats, but he could quite have easily chosen the Labour party as a comparison. All are in the post-mortem stage: pondering how they got the election so wrong and desperately searching for the path back to public credibility.
More than ten companies provided regular national polls during the campaign, but it was Lord Ashcroft who offered the most detail on specific marginal seats. The reputation of the once-reviled peer had been reinvigorated through a £3 million operation that surveyed an impressive 167 constituencies. His freely available research seemed to give more detail than ever before on how an election would turn out in the places that mattered.
But looking over the database now shows how misplaced that confidence was. Ashcroft polled 167 constituencies and had the eventual winner ahead in only 103 of cases – a success rate of 62 per cent. For the polls that were published after the short campaign began on 30 March, the success rate was still only 63 per cent. The largest gaps between poll and result were not confined to any type of seat in particular. Let’s take some examples:
- Cannock Chase: On 27 April, Ashcroft had Labour six percentage points ahead. Result: Tories won by 10.5 points.
- Castle Point: On 27 April, Ashcroft had the Conservatives five points ahead of Ukip. Result: Tories won by 19.7 points.
- Cornwall North: On 1 May, Ashcroft had the Liberal Democrats two points ahead. Result: Tories won by 13.7 points.
- Dumfriesshire, Clydesdale and Tweeddale: On 1 May, Ashcroft had the SNP 11 points ahead. Result: Tories won by 1.5 points.
- Harrow East: On 8 April, Ashcroft had Labour four points ahead. Result: Tories won by 9.7