David Cowling, editor of the BBC Political Research Unit, has posted this today on the BBC website's Poll Watch: Analysis:
A Sun newspaper poll, carried out after the TV debate, suggests Labour are in third place on 28% (down 3%), with the Lib Dems on 30% (up 8%) and the Conservatives 33% (down 4%). Applying the figures from The Sun poll, which came from a YouGov survey of 1,290 people, to the BBC News website's election seat calculator, results in the following: Labour 276 seats; Conservatives 245 seats; Lib Dems 100 seats; Others 29 seats.
This is the first national poll sampled after Thursday's debate. Clearly the findings, if confirmed by the polls expected on Sunday, are important. It is worth pointing out that the two point difference between the Liberal Democrats and Labour is within normal sampling error, so it does not mean Labour is definitively in third place.
Although the headline focus may be on the Liberal Democrats appearing ahead of Labour we should not ignore the poll's suggestion that the Conservative fall in support is bigger than Labour's.
Perhaps it is best to consider this single poll as an immediate referendum on Thursday night's debate, until we have evidence, if any, that it represents the settled will of British voters.
Why does Mr Cowling emphasize the possibility of a sampling error concerning the 2% Lib Dem lead over Labour but ignore it when foregrounding the additional 1% fall in support by the Conservatives (4% compared to 3% for Labour)? Surely we 'should not ignore' that the 'normal sampling error' also 'does not mean' 'that the Conservative fall in support is' 'definitively' ' bigger than Labour's'.