Latest ICM and Survation voting intentions
Two new voting intention polls today. The first by Survation for Good Morning Britain had topline figures of CON 48%(+1), LAB 30%(nc), LDEM 8%(+1), UKIP 4%(nc). Clearly there is no substantial change since their poll a week ago. Fieldwork was conducted on Friday and Saturday, after the leak of the Labour manifesto, and doesn't show any sign of any impact.
The second was the weekly ICM poll for the Guardian. Topline figures there are CON 48%(-1), LAB 28%(+1), LDEM 10%(+1), UKIP 6%(nc). As many have noted, ICM are now are, along with TNS, one of only two pollsters still showing Labour support below thirty points (MORI last poll did the same, but that was several weeks ago when everyone showed Labour that low). It's not that ICM haven't shown Labour support rising a little. ICM have been showing Labour recovering slightly, it's just they've been doing so at a slightly lower figures: at the start of the campaign ICM had Labour at 25-26% and they now have them at 27%-28%.
This seems to be a consistent methodological difference. The methodological differences between pollsters are complicated and various, and some of them work in opposite directions (ICM, for example, also reallocate don't knows in a way that helps Labour) but the most obvious one at the moment is probably the approach to turnout. Traditionally British pollsters have accounted for people's likelihood to vote by getting respondents to estimate their own likelihood to vote - put crudely, they ask people to say how likely they are to vote on a scale of 0 to 10, and then either weight them accordingly (someone who says they are 8/10 likely to vote is only counted as 8/10ths of someone who says 10/10), or apply a cut off, ignoring people who rate their chances below 5/10 or 9/10 or 10/10. Since 2015 several companies, including YouGov and Ipsos MORI, have also factored in whether people say they have voted in the past, weighting down past non-voters.
ICM and ComRes have adopted new approaches. Rather than basing their turnout model on people's self-reported likelihood to vote, they base it on their demographics - estimating respondent's likelihood to vote based on their age and social grade - the assumption being that younger people and working class people will remain less likely than older, more middle class people to vote. This tends to have the effect of making the results substantially more Conservative, less Labour, meaning that ICM and ComRes tend to produce some of the biggest Tory leads.
Full tabs for the ICM poll are here and the Survation poll here.
