In his article on our 11 July forecast, John Rentoul wrote:
“My view, and this cannot be based on opinion polls, is that when the voters come to choose they will shy away from the prospect of Miliband as prime minister, just as they shied away from Neil Kinnock in 1992.”
This view is not so far from being based on opinion polls as suggested. One of the possible drivers of electoral cycles is that people focus their vote choice more on whom they want to be Prime Minister as the election approaches. But even without the theory, it is fairly intuitive to expect voting intention to move towards preferences for Prime Minister as an election approaches if there is a mismatch between them in the midterm.
The current situation is that Labour have generally had a lead in voting intention despite the public having long since told pollsters they prefer David Cameron to Ed Miliband for the premiership. So we should expect the Conservatives to go up and Labour to come down in the voting intention polls before the election.
This is what my model has been predicting, albeit not explicitly or solely because of leadership effects. My model has used historical polls to estimate the extent of and consistency in electoral cycles, generally without looking at leadership evaluations.
The model does capture leadership effects to the extent that there has been an historical tendency for Prime Ministers to be better regarded than their opposition counterparts. If leadership evaluations were fully incorporated (a tricky task given the polling question isn’t asked as often) the prediction for the Tories would go up and Labour’s down.
By how much, I don’t know. But we can say that current leadership evaluations provide reason to believe in the direction of change from current voting intention polls that I have been forecasting.
A similar story could be told for economic management evaluations in the polls, which provide further succour for the Conservatives.
Elections Etc 
All opposition leaders are regarded as less electable than the incumbent prime minister. Experience and power give the leader a significant advantage. Its only in notable cases when the incumbent becomes tarnished in some way that the situation reverses as happened with GB. Had DC been in opposition to TB (prior to Iraq) he would have attracted the same unfavourable comment and poll ratings currently being seen for EM. Wilson was able to appear more statesmanlike than Heath in 74 because had already been PM.
We should also note the electorate’s frequent desire to see someone new at the top, and ‘Time For Change’ (or some similar slogan) is often the opposition party’s rallying cry.
In 1970 the pollsters expected Wilson to be returned to power – he had already won 2 elections and seemed set to stay at Number 10 – but unexpectedly the nation took a chance on Heath. In 1992, however, it was widely predicted that Britain would replace Major and the Tories with the (untested) Kinnock. Up until the final day or two the pollsters were wrong and Major scraped a victory.
I’m not sure what conclusion to draw. Perhaps we should just bear in the mind that the electorate can be unpredictable!