Rob Hayward, who called the 1992 polling failure (and whose analyses are always worth paying attention to) has told the Guardian he thinks there is some skew in the polls now, citing the local election results – which were less bad for the Conservatives than might have been expected based on Westminster polls – and the makeup of undecided voters in those polls.
Local elections
Over the weekend I spoke to Polling UnPacked on precisely this topic, particularly with regard to the local election results, and what I see as the differences between now and 2015 when it comes to potential polling error. The whole post is worth reading, but it quotes the following summary of my thoughts:
I think the key differences [between now and 2015] are that it’s only one thing rather than everything, and in terms of “real votes”, chiefly Westminster by-elections, this looks nothing like 2015 (both Labour and Lib Dems have been getting mid-90s level swings)
I also think there are other explanations for the narrower gap in local elections than you’d expect given the polls. We know for sure that the squeezable votes are much more on the left (or at least, lean Labour over Conservative right now). The system is more fragmented, ticket-splitting may be higher, the age-based realignment way have moved lower turnout elections to the right, the anti-governing party bias may be less than it was, and so on.
Don't know, do matter
But what about people who say they'll probably vote, but don't know which party's box they'll tick? This is a big deal. After the 1992 disaster, pollsters recontacted their respondents and found that their don't knows had broken heavily for John Major, in many cases having also voted for Margaret Thatcher in 1987. This led to the suspicion than they hadn't genuinely been undecided and had in reality intended to vote Conservative all along (the Shy Tory Factor).
Whether this was really the case or voters had simply reverted to habit doesn't really matter – the point is that undecided voters do tend to return home. And in 2024 they are, once again, more like to be Tories. But unlike in 1992, most pollsters account for the composition of don't knows. Some of them ask a followup "squeeze" question, others use reallocation or imputation (which can get very complicated)
Others, however, don't do this, which most likely accounts for a chunk of the differences between the results that different pollsters are getting. Although with so many moving parts, there could be other things at play too. What we do know is that the number of undecideds tends to decline during the campaign as voters make their minds up, in which case we would expect to see convergence between different methodologies.
Sense check
We did get a useful sense check a few weeks ago on Super Thursday, where several of the mayoralties were polled. These races are becoming a lot more about the candidates, in a way that's historically been more common in the US than the UK, but the polling was candidate specific, so should be a good indicator of sample versus reality.
The average errors (which Andy Lawton helpfully compiled) across all polls and all races on 2nd May give a net skew of 3.3 points towards Labour, which is roughly its historical average in Westminster elections. So if (and it's reasonably-sized if) you can extrapolate to voters who only vote in general elections, then you end up at the narrower end of the range of polls than the middle.
The Guardian piece anonymously quotes another "polling industry expert" as expressing concern about the potential for polling error for data quality reasons – which some panels do indeed seem to be struggling with – but which don't obviously skew the risk to accuracy in any particular direction.
So there is no consistent pattern of red flags in polling, as there was in 2015 and 1992.
Early polls
As for what voting intention polls are doing since the campaign started, well, not much. John Curtice has worked out that the average changes for each of the top four parties, across the four polls we've had so far, compared with the same pollsters' last pre-campaign polls, to the nearest percentage point, is zero.
We are expecting a new VI poll from Survation this afternoon.
The generation game
We have had some policy announcements from the parties, for which relevant polling has been published. The Tories' proposal to reintroduce national service – widely seen as targeting Reform switchers – is hard to poll, because how the public feels about it depends on the details. Thankfully YouGov polled multiple variations last year, and found that voluntary national service had, on the face of it, net support, but compulsory schemes didn't, while those in the community were more popular than those in the military.
Labour restated its plan to reduce the voting age to 16. While elite opinion on this issue splits very much along party lines, public opinion seems sensitive to framing. Ahead of the EU referendum, an Ipsos split sample famously gave wildly different results for different question wordings.
At the other end of the age spectrum, the Conservatives announced that they would add a fourth leg to the triple lock. In real life (as opposed to on Twitter) the intergenerational balance when it comes to spending isn't generally seen as unfairly favourable to older generations. Though that may not stop a debate around the juxtaposition of this and their national service announcement...
