ICM have released their August poll for the Guardian. Topline voting intention figures are CON 40%, LAB 31%, LDEM 7%, UKIP 10%, GRN 4%. Full tables are here.
This is the first ICM poll since the election to feature an updated methodology in light of the polling error. Since 1993 or so ICM have reallocated people who don’t give a voting intention based on how they say they voted at the previous election. Colloquially this is often known as a “shy Tory” adjustment, as when it was initially introduced in the 1992 to 1997 Parliament it tended to help the Tories, though after the Iraq war it actually tended to be a “shy Labour” adjustment, and in the last Parliament it was a “shy Lib Dem” adjustment.
In practice ICM didn’t reallocate all their don’t knows and refusals as many people who refuse to give a current voting intention also refuse to say how they voted at the last election (ICM call these people “total refusals”, as opposed to “partial refusals” who say how they voted last time but not this time). Under the new method ICM are also attempting to estimate the views of these “total refusals” – they are reallocated at the same rate as “partial refusals” but are assumed to split slightly more in favour of the Conservatives, based upon what ICM found in their post-election re-contact survey. The effect on this change on ICM’s headline figures this month is to increase the level of Conservative support by one point and decrease Labour support by one point.
The implication of this adjustment is that at least some of the error at the general election was down to traditional “shy Tories”, that those who refused to answer pollsters’ questions were disproportionately Conservative supporters. However, from being on panels with Martin Boon since the election and hearing him speak at the British Polling Council inquiry meeting I don’t think he’ll have concluded that “shy Tories” was the whole of the problem, and in ICM’s tables they are clear that they “expect to produce further methodological innovations in the future.”