Election 2017: Pre-election polls have underestimated 'Shy Tory' effect, says leading pollster

'My sense is that certain approaches to polling [prior to election day] will have underestimated the amount of people likely to vote Conservative,' says ComRes pollster

A leading pollster has warned polling in the lead up to election day has underestimated the so-called “shy Tory” factor.

The term “shy Tory” was coined in 1992 and came to fruition after pollsters wrongly predicted the election result. While polls had shown Labour and the Tories to be neck and neck, the Conservatives won by eight points.

Despite the fact pollsters have since endeavoured to modify their methodology to mitigate against the phenomenon, it is a persistent problem which many argue has reared its head ever since.

Dan Holden, who is in charge of politics for ComRes, has suggested other polling companies have misjudged the “shy Tory” factor. He argued their techniques and methodologies had failed to do enough to alleviate the phenomenon.

In their final poll for The Independent, published on Wednesday afternoon, ComRes found Ms May was on course for a definitive victory over Jeremy Corbyn and would enjoy a 10-point lead.

“My sense is that certain approaches to polling [prior to election day will have underestimated the amount of people likely to vote Conservative,” he said.

“We try and dig below the surface in the questions we pose. We ask a series of questions which go from ‘did you vote last time?’ ‘who did you vote last time?’, as well as asking them who they would vote for if they were legally required to. I think we go more in depth than other polling firms”.

But Mr Holden admitted the slippery, evasive phenomenon was something impossible to ever wholly and water-tightly protect against, saying: “We can do our best to take the "shy Tory" factor into account but I don’t think you can ever be truly sure that there are no shy Tories”.

But Mr Holden explained the most significant difference between ComRes’ polling methods and those used by other rival firms is their attitude to turnout. In other words, the main problem lies with the disorganised Labour voters rather than with the “shy Tories”.

“A lot of pollsters take the public at their word of how they’re going to turn out but we don’t. The big problem with the last election was turnout,” he said.

In the 2015 general election, the gulf between old and young voters was dramatic, with just 43 per cent of 18-24-year-olds going to the polls, compared with 78 per cent of people aged 65 or over.

"The big divide in our polling figures compared to other firms is we are not taking people at their word when they say they are going to turnout".

“When someone who is 24 says I’m definitely going to vote it means something very different to when someone who is 65 says I’m definitely going to vote”.

ComRes’ latest poll published before election day puts the Conservatives on 44 per cent of the vote, down three points, Labour on 34 per cent, down one, the Liberal Democrats on 9 per cent, Ukip on 5 per cent and the Greens on 2 per cent, all up one. If correct, it also puts Ms May on course for a solid 74-seat majority – the largest the Conservatives have secured since Margaret Thatcher.

Despite the fact the “shy Tory” phenomenon was frequently cited as the reason for the 2015 general election polls being incorrect, an enquiry later found polling projections had in fact been incorrect for other reasons. The most important being unrepresentative samples.