‘Lazy’, lying Labour supporters were the reason why pollsters predicted the 2015 general election result inaccurately, according to research by the British Election Study (BES).
It found that a high proportion of Labour supporters told pollsters they would vote for Ed Miliband but did not turn out on polling day, compared to a much smaller proportion of Conservative backers who did the same.
This helps to explain why polls consistently showed the two parties neck and neck right up until polling day, when the actual result gave a 6.5 per cent lead to David Cameron’s party.
The study, titled Why did the polls go wrong? casts doubt on other theories that attempt to explain the inaccuracy of the polls, such as the idea that “shy Tories” did not want to admit to pollsters they were backing the party or the suggestion that a late swing among the “don’t knows” ended up giving the Conservatives a much larger share of the vote than expected.
Nine out of ten respondents to the study claimed they voted but turnout at the election was just 66.4 per cent and although polling respondents are more likely to be politically engaged than the average voter, the BES said it had “considerable evidence that respondents overstate their turnout”.
For example, one in five respondents in areas without local elections claimed to have voted in them in 2015; up to 6 per cent of respondents said they had voted by post before the postal ballots were even sent out; and 46 per cent of respondents who the BES could not verify as registered to vote in June 2014 claim to have voted in the 2014 European Elections.
“In all of these cases, the fibbers lean significantly more Labour than other respondents,” the authors said.
The number of ‘lazy’ voters as a whole was largely unchanged from 2010, the report found, but the “differential turnout” between the two main parties widened significantly.
Labour picked up many of the Liberal Democrats’ ‘lazy voters’, while many previously ‘lazy’ Tory voters defected to Ukip.
Chris Prosser, one of the authors of the report, said Ukip draws disproportionately from the more lazy bunch of voters” and Nigel Farage’s popularity managed to “suck out some of the lazy Conservatives”.
One route to victory for Labour would be to mobilise this group of “unenthusiastic” supporters, Mr Prosser suggested, but he said it was much harder than it sounded because there were deep-rooted and often cultural reasons why they decided not to vote.
“Engaging these ‘lazy’ voters would obviously improve its chances but it’s not the most cost-effective way of winning elections because often these voters are structurally unlikely to turn out – they’re surrounded by people who don’t vote,” he said.
Mr Prosser added that while the “fibbers” made up a small section of the electorate, small errors can have big consequences when the polls are so close and the stakes are high.
Pollsters were widely criticised for calling the general election incorrectly and the British Polling Council is conducting an inquiry into the apparent “bias” given to Labour in polls across the board. But the BES study concluded that if its “differential turnout” theory is the primary cause of the polling inaccuracy, it is “relatively good news for pollsters” because they can now use turnout weighting in future polling projections.
General election 2015: Polling day
General election 2015: Polling day
1/16 General election 2015
Nuns arrive to vote at a polling station at St John's Church in Paddington, London
2/16 General election 2015
A voter leaves the White Horse Inn in Priors Dean, also known as the 'Pub with no name', which is part of the East Hampshire constituency and acts as a local polling station on the day of the election
3/16 General election 2015
General view of inside the White Horse Inn in Priors Dean
4/16 General election 2015
People cast their votes as a man uses a punch bag in the East Hull Boxing Academy, which is being used as a polling station in Hull
5/16 General election 2015
Penny Higbee waits to greet voters at her home in Routh, East Yorkshire, which is being used as a rural polling station
6/16 General election 2015
Voters in Ironbridge, Shropshire, arrive to cast their vote at The Iron Bridge Tollhouse
7/16 General election 2015
A voter arrives at the North West Ambulance Service Station at Milton Green, Cheshire, which is being used as a polling station as Britain goes to the ballot box
8/16 General election 2015
A polling station has been installed in a launderette in Oxford
9/16 General election 2015
SNP candidate for the Gordon constituency and Former First Minister Alex Salmond with first time voter Nicki Falconer, and her family, (L-R) Mackenzie, Nicki, Skye, Alex Salmond and Keiran at their local polling station in the Gordon constituency in Ellon, Scotland
10/16 General election 2015
Prime Minister David Cameron and wife Samantha after casting their votes at Spelsbury Memorial Hall, Witney
11/16 General election 2015
Liberal Democrat leader and Deputy Prime Minister Nick Clegg and his wife Miriam Gonzalez Durantez arrive at Hall Park Hill Community Centre to cast their votes, in Sheffield
12/16 General election 2015
Labour Party leader Ed Miliband and his wife Justine Thornton leave the polling station at Sutton Village Hall in Sutton after casting their votes in the 2015 general election in Doncaster
13/16 General election 2015
First Minister of Scotland and leader of the SNP Nicola Sturgeon, votes with her husband Peter Murrell in Glasgow, Scotland
14/16 General election 2015
Ukip leader Nigel Farage arrives to cast his vote for the South Thanet constituency in Ramsgate
15/16 General election 2015
Plaid Cymru leader Leanne Wood arrives at a polling station in Penygraig, Rhondda, Wales
16/16 General election 2015
Green Party leader Natalie Bennett after casting her vote at Ossulston Tenants' Hall, London