Can Opinion Polls Really Say Who Will Win The Election?

The 2024 general election has been the most “polled” in British history. More companies have conducted more polls, and with a greater variety of methods, than in any previous contest.

- SEAN O'GRADY

In terms of seats, the predictions have varied wildly – from around 55 seats for the Conservatives up to around 200.

One fact, though, has been remarkably constant since before the beginning of the campaign – indeed, since at least the start of the year. Labour has enjoyed a consistent lead of around 20 percentage points over the Conservatives, and the nearcertainty of forming the next government with at the very least a substantial majority. Still, there are some interesting questions to be asked...

Could the polls be wrong?

Yes. They were wrong in 1970, 1992 (the worst errors) and 2015, for example. Even in elections that yield very clear winners, such as the one in 1997, the polls can be out, but in a landslide scenario nobody much cares.

The usual rule for conventional polls is that any given party can be about three percentage points out in either direction, in 19 out of 20 polls – meaning there will be some “rogue” outliers. It’s best to survey the whole scene, not focus so much on lead (which doubles the margin of error), and to watch for broader trends.

Will they be wrong this time?

With so many polls employing so many radically different methods, they would all have to be out for different reasons, but in the same (pro-Labour, pro-Reform) direction, and at such a historic scale, that they’re unlikely to be giving a completely bogus picture.

What goes wrong?