Comparing Boris and Dave
Boris Johnson's victory in London has produced the predictable flurry of media speculation about Boris as a future leader. Both the polls in the weekend papers - YouGov in the Sunday Times and Survation in the Mail on Sunday had a series of questions comparing Boris and David Cameron and both suggested Boris would do very marginally worse than Cameron.
Polls on alternative leaders are a tricky thing to do, and of dubious worth. Journalists love them as they produce nice easy headlines, but they are often done very badly indeed and even if done well, still have problems.
To start with the methodological problems, firstly you need to ask voting intention in exactly the same way - if you normally filter by likelihood to vote and reallocate don't knows, you need to do that in your hypothetical question too, otherwise any difference could be down to that (including asking likelihood to vote afresh, you cannot assume it would stay the same). Neither can you say "Imagine Boris Johnson was leader" as it gives undue prominence to one party leader, you have to mention all three. However, you can't then compare it to a normal voting intention question, as they don't mention the party leaders - what if any change in the answer is actually down to mentioning Ed Miliband or Nick Clegg? Instead you need to do a control question.
In YouGov's poll they asked two questions. The first asked how people would vote if the party leaders at the next election stayed the same, the second if the party leaders were Johnson, Miliband and Clegg. You might expect the first one to be the same as the current headline figures - it is not. Current voting intention is CON 31%, LAB 43%, LDEM 9%. If you ask people how they will vote at the general election if the leaders are still Cameron, Miliband and Clegg the answer is CON 32%, LAB 40%, LDEM 10% - mentioning Cameron, Miliband and Clegg in the question reduces the Labour lead by 4 points.
This is interesting in its own right - perhaps more interesting than the Boris comparison! Is it people consciously thinking to themselves that while they'll say Labour now as a protest, but probably won't actually vote that way come the election? Or a positive effect from mentioning Cameron, or a negative effect from mentioning Ed Miliband? It's impossible to tell.
YouGov then asked the same question with Boris Johnson as Tory leader, this changed the figures to CON 32%, LAB 41%, LDEM 11%. So under Boris the Conservatives would perform the same, but Labour and the Lib Dems would do slighter better (it looks as though the Conservatives would lose support to the Lib Dems and Labour, but presumably it is cancelled out by gaining support from Others and Don't knows). Even this, however, shouldn't be given too much weight, as people don't tend to be very good at answering hypothetical questions about how they would vote if X happened. People don't know what policies Boris Johnson would promote, how he'd handle the job, so the answers are based on pretty flimsy information (not, one should add, that people's eventual voting intentions are necessarily based on a much greater understanding.)
YouGov also asked whether people were suited to be Prime Minister, and were in touch with the public. On being "Prime Ministerial" David Cameron did substantially better than Boris Johnson and, indeed, the other people asked about. 44% of people thought David Cameron was well suited to being Prime Minister, compared to 24% for Boris Johnson (Ed Miliband was on 25%, George Osborne just 10%). Of course, actually being Prime Minister is a big help in people seeing you as Prime Ministerial! On understanding the problems faced by ordinary people only 21% thought Cameron understood well, behind Boris Johnson on 27% (and Ed Miliband on 32%).
Survation in the Mail on Sunday also asked some Boris Johnson questions. They asked if people were more or less likely to vote Conservative with Boris in charge. More or less likely to vote X if Y questions come with another whole bucketload of problems which I won't go into today, but they found a similar situation anyway - 22% said more likely, 24% less likely.
Survation also asked a series of questions on whether people rated Boris or David Cameron on various attributes. Boris was seen as more likeable, charming and more in touch. cameron was seen as having better leadership qualities, being more true to Conservative values, better at taking tough decisions, more trusted on the recession and likely to be a better Prime Minister. They scored equally on intelligence.
Personally, I suspect the practical requirement to be a member of the House of Commons at the time a leadership vacancy arises and the timing difficulties around that are a huge block to Boris Johnson ever being in the running for the party leadership. Nevertheless, what data we have does not suggest he is any sort of panacea for the Tories.
