Will the Campaign Make a Difference? (TLDR: No)








23rd May 2024

On Day One of the General Election campaign, the Labour Party leads the Conservatives in the polls by 22 points. Against this backdrop, Rishi Sunak’s hopes of remaining in Downing Street after July 4th rest on two possibilities: either the polls narrow dramatically between now and election day, or else they prove to be catastrophically inaccurate.

How likely is it that the polls narrow significantly before July 4th? Well, historically, campaigns make little to no difference. This message might not be well-received in Downing Street, but if we judge campaign impact as movement in the polls from the point of announcement to polling day, Mr. Sunak’s chips are cooked. The evidence is stark: in UK general elections since 1992, the average change in the Conservative/Labour lead during the campaign has been just under four percentage points. Reminder: he currently trails by 22 points.

Famously though, the change during the campaign has occasionally been much higher. When Theresa May called her snap election in 2017 her party was, on average, eighteen points ahead in the polls, but by the final days of the campaign her lead had shrunk by almost two thirds. The eventual results were even worse, and cost May her majority. But everyone agrees her campaign was apocalyptically bad – and 2017 should be considered a monumental outlier as far as this analysis is concerned.

So the Tories romping back to the front of this horserace based on a highly effective campaign? Not likely, and probably even less so with the generally unimpressive campaigner that the Prime Minister is seen to be at the helm.

What about Sunak’s other hope – that the polls are wrong? Since 1992, the average polling error at general elections in terms of the Conservative/Labour lead has also been just under four points. It was largest in ’92, when polls on the eve of the election said the race was too close to call; in the end, John Major’s Conservatives beat Labour by seven-and-a-half points.

Certainly though, there is a chance here. Polling misses at home and around the world are too frequent to rule out. In the UK, polls were plain wrong in 1992 and 2015 in particular, and most pollsters have been wrong some of the time. Recently, there have been high-profile misses in Slovakia, the Netherlands, Australia and Turkey and we could go on, but that’s not the point. The point is that in every case, it is the party of the Right which has been underestimated. Martin Boon has written on this subject extensively, and it would be no surprise if current polling overstates the Labour lead – we just need look at some of the very recent London Mayoral polling to understand that this phenomenon has not gone away.

But there’s wrong and there’s historically wrong, and the Tories need to be begging for the latter. Sometimes the error in the polls and the fluctuations during the campaign compound each other, and sometimes they cancel each other out. Sometimes they benefit the incumbent, and sometimes they benefit the opposition. For Sunak to make up the current deficit in the polls, he needs all of these factors to align in his favour. Moreover, he needs them to be extreme in scale. Even the largest change in lead during a campaign (eleven points in 2017) plus the largest polling error in recent history (seven-and-a-half points in 1992) would not be enough to close the gap. Labour would still win the most votes, and the most seats.

So the Tories clawing their way back into contention? It would only be in the form of a monumental shock as the first results drip-feed in, but even that is more likely than a blistering campaign which sees Sunak overturn years of hostile polling. Overall, the probability of a Tory comeback is infinitesimally small in the context of where we now stand at the outset of all this psephological fun.

Will the campaign make a difference, bringing the Tories back into contention? Probably not in this universe.

The data for this analysis was taken from Mark Pack’s PollBase:  https://www.markpack.org.uk/opinion-polls/

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Matthew PriceAuthor: Matthew Price