New research has revealed the bias of different UK polling firms.
A team of researchers at Manchester University, called the “Polling Observatory” measured what they called the “house effect” as part of a big change in calculating averages.
Although it has been generally acknowledged that different polling companies produce results that are particularly beneficial to one party or another, this is the first time that bias has been measured.
According to Political Betting, the team say:
“Our new method makes it possible to estimate the ‘house effect’ for each polling company for each party, relative to the vote intention figures we would expect from the average pollster.
“That is, it tells us simply whether the reported vote intention for a given pollster is above or below the industry average. This does not indicate ‘accuracy’, since there is no election to benchmark the accuracy of the polls against.
“It could be, in fact, that pollsters at one end of the extreme or the other are giving a more accurate picture of voters’ intentions – but an election is the only real test, and even that is imperfect..”
The polling firm that is friendliest towards the Conservatives is Populus, giving them 2.3 percent above the average, while the most hostile is Survation, putting them 1.8 percent below average.
UKIP are the party with the biggest variation. Survation puts them a massive 4.4 percent above average, while ComRes phone polls give them 2.5 percent below average. Curiously, ComRes online polls put the party 1.8 percent above average.
YouGov are Labour’s most generous pollsters, giving them an advantage of 2.1 percent, while Survation are harshest on Miliband’s party, putting them 1.5 percent below average.
Meanwhile, the best polling firm for the Liberal Democrats is ICM, giving them 2.8 percent above average, while Opinium put them 2.3 percent below.
One of the more curious results is that the polling firm of Conservative peer Lord Ashcroft puts his party 0.7 percent below the average, while putting UKIP 0.9 percent above. The firm is even harder on Labour and the Lib Dems, however, putting them 0.8 percent and 1.2 percent below average respectably.