I thought it a good opportunity to provide a round up of the available evidence we have about what the public think of airstrikes against Islamic State in Syria… and to give a reminder to people of what is NOT good evidence. First, here’s the recent polling evidence:

• Survation/Mirror polled after Cameron’s statement this week, and found 48% agreed with Britain beginning airstrikes against Islamic State alongside France and the US, 30% of people disagreed (tabs here)
• YouGov earlier this week asked if people would approve or disapprove of the RAF taking part in airstrikes against ISIS in Syria. 59% would approve, 20% would disapprove (tabs here).
• ComRes for the Indy on Sunday asked a question on whether people would support Britain taking part in airstrikes against ISIS without UN approval (there wasn’t a parallel version with UN approval). 46% would support airstrikes without UN approval, 32% would not. Tabs are here. A slightly earlier ComRes poll for the Daily Mail asked if people would back British military air strikes against Syria – 60% would, 24% would oppose (tabs here)
• BMG for the Standard asked a question on whether Britain should extend it’s current airstrikes against ISIS in Iraq to cover Syria as well. This found an even split – 50% thought they should, 50% thought they should not (tabs here)
• I don’t think ICM have asked a direct support/oppose bombing question, but last week they asked a question about Parliamentary consent. It found 46% supported airstrikes if Parliament agreed, 23% supported airstrikes without Parliamentary consent, 12% opposed airstrikes regardless, 19% didn’t know (tabs here)

The precise levels of support differ from poll to poll as they are all asking slightly different questions using slightly different wordings. However the overall picture is pretty clearly one where the balance of public support is in favour of airstrikes – even the most sceptical finding, from BMG, has people evenly divided. That’s not to say British public opinion is gung-ho enthusiasm for conflict, if you look through the rest of those surveys there is plenty of doubt (for example, several polls have found that people think intervening will increase the risk of terrorism here in Britain). On balance, however, public opinion seems to be in favour.

On twitter and other social media there is lots of sharing of a “poll” by ITV that apparently shows a large majority against Britain taking part. The reason this “poll” gives such sharply different answers is because it is not representative and has no controls upon it. I have written about this many, many times (and for many decades before I was writing the great Bob Worcester dutifully fought that same long fight). The sort of open access polls that used to be on Ceefax, and for people to phone in to newspapers, and these days pop up at the bottom of newspaper stories and the sidebar of websites are completely useless as a way of accurately measuring public opinion.

Opinion polls are meaningful for one reason and one reason alone, because the sample is representative. It has the right number of young people and old people as Britain as a whole, the same number of rich people and poor people as Britain as a whole, the same numbers of left-wing and right-wing people… and therefore, it should have the same proportion of people who are anti-bombing and pro-bombing as there are in Britain as a whole. An open-access poll on a website has no such controls.

When a poll is properly done the researcher will use some sort of sampling method that produces a sample that is demographically representative of the country as a whole. Then when it’s finished, they’ll fine tune it using weighting to make sure it is representative (e.g. if the proportion of women in the sample is lower than 51% they’ll weight the female respondents up). The people answering the poll will be invited and contacted by the researcher, preventing people or organised campaigns skewing a poll by deliberately directing lots of people who share their views to fill it in.

Numbers alone do not make a poll representative. A common error is to see a professionally conducted poll of a 1000 people and a bigger open-access “poll” of 10,000 people and think that the latter is therefore more meaningful. This is wrong – it’s how representative the sample is that matters, not how big it is. The classic example of this is the 1936 US Presidential race, the one that made the reputation of George Gallup. Back then the Literary Digest conducted a mail-in poll with a sample size of 2.3 million people, Gallup conducted a normal sized professional poll. The Digest’s poll predicted that Alf Landon would easily win the election, Gallup correctly predicted that Roosevelt would win a crushing landslide. The problem was that while the Literary Digest’s poll had a vast sample (probably the biggest sample of any opinion poll, ever) it wasn’t representative, it was skewed towards richer people who were more likely to vote Republican. Gallup’s sample was tiny compared to his competitor, but it had proper controls and was properly representative.

Unlike the polls by ComRes, ICM, Survation and YouGov the ITV “poll” won’t have controls to make sure the sample is representative of the British public – indeed, they don’t even collect any demographics to see whether it is or not. There is nothing stopping organised campaigns seeking to influence an open poll – for example, StoptheWar could’ve sent an email out to their mailing list encouraging them all to fill it in. There is nothing stopping anyone with the wherewithal to delete a cookie from their computer voting many, many times. It is, in short, meaningless.

Following May the properly conducted polls got something wrong too of course – but that’s a reason to be wary of even properly conducted polls, not a reason to suddenly put trust in “polls” that don’t even attempt to do things properly.

“Polls” like this, which Bob Worcester christened “Voodoo polls”, are a blight on journalism and opinion research. Because to the casual observer they can’t be easily distinguished from a properly conducted poll they mislead readers into thinking they are meaningful. I assume newspaper websites use them because they drive traffic, but serving up “news” that any journalist with a basic grasp of stats should know is meaningless – or in this case, actively wrong – is doing a disservice to their readers and listeners. At least when the BBC do things like this caveats are normally added saying the “poll” was self-selecting and isn’t representative. ITV don’t caveat it at all, so who can blame all the excited anti-airstrikes people on social media for thinking it means something and jumping upon it? I’m sorry, but it doesn’t – properly conducted polling suggests the public split broadly in favour.

Of course, none of this means that it is necessarily correct for Britain to take part in airstrikes. Polls are not a magic 8 ball where you ask the public and they spit out the “correct” answer. Public opinion can be wrong, and often is. The evidence is that public opinion favours bombing ISIS in Syria, it doesn’t necessarily follow that the government or opposition should do so.

Today’s Times has a new YouGov poll of Labour party members and registered supporters (so members, registered trade unionists and £3 supporters – the same group who were able to vote in the Labour leadership election). Full tabs are here.

65% thought Jeremy Corbyn was doing well as leader, 34% badly as leader. Less promisingly, only 46% think it’s likely Labour will win the next election under Corbyn and only 38% think it’s likely he will ever be PM. Labour party members think Corbyn is doing well and expect him to lose. This apparent contradiction is easily resolved: 56% of Labour members think parties should say what they believe, even if it’s unpopular and loses elections, in comparison 32% think they should compromise in order to put foward policies that allow it to win an election and put policies into action.

Looking forward there is little appetite amongst Labour members for a change of leader: 57% think Corbyn should remain leader and fight the next election, 20% think he should hand over the leadership to someone else at some later point during the Parliament, 18% think he should go now.

There’s a sharp division between those who voted Corbyn and the minority who didn’t – 86% who voted Corbyn think he’s doing well, 66% who didn’t vote Corbyn think he’s doing badly. 82% of people who voted Corbyn think he should stay till the election, 43% who voted differently think he should stand down now. The vast majority of people who voted for Corbyn think he is doing well and think he should stay on, at least for now; there is no sign at all of buyer’s remorse amongst Corbyn’s voters. Equally, Labour party members who opposed Corbyn in the leadership election continue to oppose him, there is little sign of them rallying round their new leader. The Labour party remains divided.

It’s quite hard to judge whether these figures are good or bad. Surveys of party members are quite rare, most of the time they only happen in the middle of a leadership election when there is no incumbent leader whose ratings we can compare. There were no polls, for example, of Labour party members when Ed Miliband had been in the job for a few months that we can compare to see if David Miliband supporters had rallied round the leader or all still wanted Ed to resign.

79% think the shadow cabinet is divided, but Corbyn’s opponents are much more widely blamed for this than Corbyn himself – 54% think the fault is mostly his opponents’, 19% Corbyn and his allies, 25% both equally. On balance, there is support amongst the Labour selectorate for mandatory re-selection of MPs – 39% think MPs should be automatically reselected unless they’ve failed badly or are very unpopular, 52% think all MPs should face a full reselection anyway.

Finally YouGov asked about two specific policy issues facing Labour. On Europe the party membership is clear: 80% would vote for Britain to stay in the EU and 62% think Jeremy Corbyn should actively campaign in favour of EU membership. On Syria Labour party members divide two-to-one against airstrikes and three-to-one against the use of British ground forces in Iraq or Syria. 48% of Labour members think Corbyn should oppose the RAF taking part in airstrikes against ISIS, only 25% think he should support them.

Ipsos MORI’s monthly political monitor for the Standard is out today – topline figures with changes from last month are CON 41%(+5), LAB 34%(+2), LDEM 7%(-3), UKIP 7%(-5), GRN 4%(+1). The big drop in UKIP support is probably nothing, last month’s poll had them jumping up five points, this month has them dropping the same amount, both the up and the down are likely normal sample variation.

The rest of the poll included some interesting questions on spending and the deficit ahead of next week’s autumn statement. During the last Parliament the government’s cuts were often unpopular, but the public consistently regarded them as being necessary. MORI’s poll suggests potential trouble for the government there – two-thirds of people still think the cuts in the last Parliament were necessary, but support for further cuts is far lower. 34% think that it is still necessary to make more cuts, 32% think cuts in the last Parliament were necessary, but it’s not necessary any more, 27% think cuts were never necessary in the first place.

Asked where any cuts should and shouldn’t fall international aid, as usual, comes top on the things people would like to see cut (59%), followed by benefit payments (36%), then defence (19%). On things they’d like to see protected from cuts the NHS, as usual, comes top (73%), followed by schools (39%) and care for the elderly (28%). Full tabs for the MORI poll are here.

ComRes also have new polling for the Daily Mail today (full tabs here). Support for British airstrikes against ISIS in Syria was similar to YouGov’s poll yesterday (60% support, 24% opposition), support for intervention on the ground was higher than YouGov’s poll – in a generic question people supported British troops getting involved in a ground war against ISIS by 50% to 31%, when asked if they’d support British grounds getting involved alongside the US or France support rose to 59%.