A big issue for political gamblers in the UK is how you do distinguish between the two polling organisations that were most accurate with the 2001 General Election and who both claim to be “Britain’s most accurate pollster” ICM and YouGov?

Is ICM, the Guardian’s pollster, overstating what Labour will get at the General Election because it is giving too much weight to people who say they are not certain whether they will vote?

This is a critical question for political gamblers for currently ICM is showing a split of LAB-37,CON-32: and LibD 22%. This is by far the biggest Labour lead and contrasts sharply with YouGov which is predicting a Conservative lead which, as we showed last week would make a dramatic difference to the way the next House of Commons looks.

At the moment, at least, the spread betting markets seem to lean more towards the YouGov view than ICM.

Understanding how ICM produces its figures is important in order for political gamblers to determine how much significance to attach to the firm’s monthly findings.

Each ICM interviewee is asked to rate on a scale of 1 to 10 their likelihood of voting with 10/10 being “absolutely certain”. This was the detailed response in the April survey:-

235 said LAB: 10-52%; 9-6%; 8-13%; 7- 6%; 6-4%; 5-10%; 4-1%; 3-4%; 2-1%; 1-0%

196 said CON: 10-65%; 9-11%; 8-8%; 7-5%; 6-1%; 5-6%; 4-1%; 3-2%; 2-0%; 1- 0%

136 said LD: 10- 55%; 9-%; 8-11%; 7-8%; 6-2%; 5-7%; 4-2%; 3-3%; 2-2%; 1-0%

Looking at the detailed breakdown it is clear that Conservatives say they are much more likely to vote than Labour supporters. The critical thing is the weighting to attach to these answers. The Mori polling company asks a similar question for its political monitor and only includes those responses from people who say they are “certain”.

With the April ICM survey a totally different picture emerges if you just include those who are “absolutely certain” or are 90% sure. Politicalbetting.com has done that recalculation and this is how it would look:-

LAB 33.5%
CON 36.8%
LIB D 21.5%

What is remarkable at the moment is that whichever pollster is carrying out the survey or however you crunch the numbers the result for the Lib Dems is, within a very small margin, the same.

We have raised thepoints in this post directly with ICM and will publish its reply.

Illustration – www.makevotescount.org.uk