Is this why the Lib Dems do so badly with the pollster?
One of the great puzzles of modern polling is why the Lib Dems always seem to have the lowest shares with the internet firm, YouGov. Thus the latest 14% total compares with the 21% that ICM was reporting in its latest survey. Clearly there’s something about the methodology of the two firms that causes such a disparity.
Thanks to data that was prepared for last Friday’s British Polling Council conference it’s now possible to make a firmer guess as to why this is happening. For unlike the other firms YouGov weights its samples according to the main newspapers that those it polls say they read.
The trouble is that the pollster seems to have a shortage of Sun/Star readers and the views of those that are questioned get magnified. On the other hand the voting choices of Guardian and Independent readers have to be scaled down because YouGov gets too many of them.
So according to the sample data given to the conference the views of two Sun/Star readers are worth a total of five Guardian/Indy readers
For the target proportion of Sun/Star readers that the pollster seeks to have in each survey is 25%. If, as is usual, they don’t get that then the opinions of those that have responded are given greater weight to bring them up to the target number. This works in reverse with Indy/Guardian readers of which YouGov always seem to have a surplus.
We looked at this last in March 2005 a couple of months before the general election. Then I mischievously suggested that those PB-ers who were on the YouGov panel could change their profile in order that their views would matter more. This is something that I did myself and for the whole of the election period I was swamped with one YouGov survey after another.
In fact I continued to be polled by the firm until I shared a cab with the YouGov chairman, Peter Kellner, and foolishly told him what I was doing. The outcome was that I got banned. At least he picked up the cab fare!
Neither the Sun or the Star are known for having a high proportion of Lib Dems amongst their readership. The Indy and Guardian are. Maybe this is why the party polls so badly with the firm.