Exit polls on the EU referendum
Following the FT story about hedge funds and exit polls, it's probably worth setting out some facts about exit polling and the referendum. I have not a clue whether the FT story is correct, but for those interested here's what we can say about exit polls at the referendum.
There will not be an official exit poll for the referendum. At general elections the BBC, ITN and Sky normally jointly fund an exit poll. The fieldwork is normally conducted by Gfk and Ipsos MORI, and then John Curtice, Steve Fisher and the rest of their team use the data to project seat numbers. This did not happen for the Scottish referendum or the AV referendum, and it won't be happening for the EU referendum either.
The way exit polls are done at general elections can't be done for a referendum. I'm not privy to the BBC's discussions, but my guess is that the reason they are not doing an exit poll is for technical reasons: the method the exit poll team use for general elections would not and cannot work for a referendum. Here's why. At general elections the team try to revisit the same polling stations at each election (obviously some are added as electoral battlegrounds change, but the core remains the same) the projection is then done by looking at the changes in support in those polling stations since the exit poll five years before. Curtice, Fisher and colleagues will look at patterns of change (e.g, are there bigger or smaller changes in different regions, or where there are different parties in contention) and use that to project the swing across different types of seat. While the overall swing can be used to come up with national shares of the vote, that's very much a by-product, at its heart the exit poll is all about change since the last election.
For obvious reasons this is not an option at a referendum: there was not a previous EU referendum a few years back that we can draw changes from. This means the exit poll method that has been so successful at the last three general elections cannot be used for referendums, and presumably as a result of this, the BBC, ITN and Sky have chosen not to have an exit poll at all.
Someone could still do an exit poll in theory, but who knows whether it would be accurate or not. It is possible to do exit polls in other ways. Instead of looking at swing, one could try and sample from a random selection of polling stations and work out national shares of the vote. This used to be how exit polls were done in this country before the current method was developed. Don't fall into the trap of thinking it would necessarily be as accurate as the recent BBC exit polls though: back in 1992 the exit poll was conducted this way, and was almost as inaccurate as that year's pre-election polls.
It is illegal to publish an exit poll until the polls have closed. Exit polls are the only type of poll that has specific laws around their publication. Under the Representation of the People Act it is illegal to publish any poll based on the responses of people who have already voted until the polls close at 10pm. There is no legal restraint on carrying them out (after all, Gfk and MORI do it at every general election), the legal bar is on publishing them while people are still voting.
Any results from much before 10pm would be of questionable use anyway. Anyone with any experience of elections knows that voting is not uniform throughout the day, there are ebbs and flows and different types of people vote at different times. Exit poll data from only the morning or only the early afternoon could be wildly misleading.
So when will we know the result? In the absence of any exit polls, we will have to wait for actual counts to take place. The Electoral Commission already has estimated result times up here. The earliest results are expected to be Sunderland, Wandsworth and Foyle, all around half twelve. Swindon, Oldham, Newcastle and Hartlepool are expected at about one. Lots of results are expected about two-ish, the bulk around three or four in the morning. Obviously how soon those results actually allow us to be confident of the overall picture depends how close it is - if all the early results show a heavy lead one way or the other we will know quite early, if they are extremely close we won't be certain till most places have counted.
On other matters YouGov had their regular EU poll for the Times this morning. Topline figures were REMAIN 41%, LEAVE 41%, Don't know/Won't vote 17%... exactly the same as a week ago. There is no obvious sign of any movement towards Leave there. Full tabs are here.
