Wednesday, 23 December 2009

The poll leads swing like a pendulum do?

Opinion polls should be treated with caution. If that aphorism needed any further emphasis it has been provided by two surveys which show starkly different results, published within two days of each other.

First, on Sunday, the Observer released its Ipsos Mori poll, which showed strong support for the Conservatives's approach to the economy and recorded a seventeen point lead for David Cameron's party.

In contrast, the Independent's ComRes poll suggests that the Tories' lead has been trimmed to nine points, with Labour up 5% since its last survey. An odd result given that Alistair Darling's Pre Budget Report was greeted, in general, with scepticism by the media.

Under the Observer's piece, Sir Robert Worcester, founder of MORI, offers something of a corrective to sensational newspaper headlines about changing poll leads.

Nine of the past 10 polls show the Conservatives at or over the 40% level, where they have been since July. Three leads were 17%, three below 10%. Not one varied in the Tory share by more than 3% from the 40% average.

It's worth noting that UK Polling Report, which is generally offers fairly circumspect analysis, is of the opinion that the ComRes version is most likely a rogue poll.

1 comment:

fair_deal said...

Angus Reid's polls with the big leads looks dodgier than (or as dodgy) as Com Res. Coffee House said Tory polls show a similar narrowing.

You Gov has been shown to have been the most reliable pollster in terms of correlation with actual results. It has shown a 9 and 12% lead.

The change is Labour has pulled itself from the mid 20's to high 20's (just touching 30 on a good day) narrowing the Tory lead.

There is also the problematic issue of by-election results which are also a useful indicator. They are not showing the type of shifts the Tories need to get the 10% swing they have to get (a far from easy task)