The Why, not the What. Could we Brits learn something about exit polling from the Americans?

Who voted for Brexit and why?

Did the Leave vote ultimately come down to a battle between old and young? Was it largely down to the white working class or was it a wider movement? Was it motivated by people’s dislike of EU laws, of regulation, or of free movement of the people. Or was it more broadly a protest vote?

The fact of the matter is we don’t know, and we will never know. Sure, we can get a hint of the answers from surveys produced by private pollsters both before and after, but as for understanding what was really in peoples’ heads as they went into the polling booths: forget about it.

We’ve all spent most of the past six months attempting to interpret the motivations of that single yes-no question, working out whether the leave vote meant people wanted a hard Brexit, wanted to maintain EEA membership and so on. Knowing why people voted the way they did would potentially change everything.

What, you might ask, does this have to do with the US presidential elections? The short answer is that when we come to analyse the reasons behind that result, we will be far better equipped than we are on equivalent UK elections (or referendums). And that comes down to the quality and depth of the way we conduct exit polls on either side of the Atlantic.

Broadly speaking, when we do the big exit polls on election day here in the UK we ask only one question: who did you vote for? In the US, voters are asked a whole range of things: about who they are (age group, race, gender etc), what they think were the most important issues in the election (the economy, immigration etc) and a whole load of other questions: how strongly do they favour the candidate they voted for, what are their attitudes towards trade, towards immigration, towards the role of government, towards each candidate and so on.

In other words, for decades the UK exit poll has sought to answer one question and answer it as well as possible – what’s the result? By contrast, when it comes to the US exit poll, the ultimate result is almost secondary. Instead, the exit poll (to give it its full name, the National Election Pool national survey) tries to explain why the country got the result it did.

So, first off, a tip for those of you watching our coverage over the course of our US election programme. I’ll be at our big screen running through the results as they come through, but I’ll also be doing something we don’t normally do in UK elections – exploring detailed poll data.

Unlike any of the other UK broadcasters, we will have access to the US exit poll data – so our coverage won’t just be about who has won North Carolina and Florida (to take two of the key battleground states) but why. If there is a Clinton landslide, where did her votes come from? If Trump swings things, how did he do it?

We hope to have these answers on the night itself – rather than leaving it for the following days.

This kind of thing matters. An election, or for that matter a referendum, is a blunt instrument: we get a binary answer, often distorted by unrepresentative electoral systems. Discerning from this the scale of a politician’s mandate is art rather than science. But having detailed polling data from (in the case of the US election) a hefty sample adds back a little dose of science.

As it happens, Britain used to collect details like this in its exit polls, until the disastrous poll of 1992, after which priorities, ahem, shifted. More money and time was spent on getting the result right than the background to that electoral decision – and, for what it’s worth, predicting the UK result is far more difficult than the US (more parties, more constituencies, more variables).

Anyway, it’s not as if the US polls are especially reliable; in fact, they have been plagued with problems in recent years – although that mostly came down to the fact that people were trying to rely on them to predict the result rather than explain it.

All the same, a glance at the way the Americans do things does raise a question: why don’t we spend more time on the day attempting to poll people to find out why they voted?

PS A disclaimer is probably necessary: Sky is one of the organisations that typically pays for the official UK exit poll. But decisions about scale are taken jointly together with the other members of the pool.