Last night, the betting markets were giving the Tories a better than 75% chance of winning a majority in Thursday’s general election. Polls still have them far ahead, and personally, I expect that they’ll do it.
If we are wrong about that, and they don’t form a majority, why might that be? If a hung parliament is coming, what would make people blind to it?
I can see four possibilities, in increasing order of likelihood:
- Something happens between now and the polling stations opening that causes people to change their minds. Something like Gordon Brown’s “bigoted woman” incident.
Not at all likely, because:
- there’s really not much time left, and,
- anyone who could be change their mind following bad behaviour by Johnson already has all the information they need – his awfulness is already priced in.
- Pollsters are repeating their mistakes from the last general election, when they greatly underestimated Corbyn’s support.
Not likely, because each polling company has a stake in being right, and particularly, in being more right than the other polling companies. Maybe there is a conspiracy to make things looks better for the Tories than they really are, but it’s pretty well hidden if so.
- Pollsters can’t model the impact of the newly-registered voters.
Unlikely, because they have a model from the last election. I expect, but don’t know for sure, that they also have some information about where these new voters are registering.
- Although their national predictions are accurate, pollsters can’t measure the impact of tactical voting, or their translation from vote share to seats is inaccurate for some other reason.
Unlikely with a large effect size. Of course there are always errors, and UK politics is in flux, but there aren’t that many marginal seats. There’s plenty of talk about this on Twitter, there’s Unite to Remain, and plenty of tactical voting sites. But while I expect Unite to Remain to have an effect, and maybe a few very close marginals to have different results, I don’t expect the effect size to be large. Most people don’t often change how they vote.
So although I think all of these are possible, I don’t think any of them are likely. I am still hoping for a hung parliament, and if that happens I will try to work out where I went wrong.