Polls have their problems. But don’t buy into the panic about local variation making the result impossible to call. If we can only gauge the national vote share, explains a member of the exit poll team, the old swingometer could still prove its worthby Stephen Fisher / November 18, 2019 / Leave a comment
Voters are volatile. The two party system has suffered a two-pronged attack. Social media campaigns are bigger, with more micro-targeting. Fake news is on the rise. Many MPs have resigned, making it easier for challenger parties in their seats. Former cabinet ministers are standing as independents. There isn’t just one national election, but 650 different contests. Many constituencies will have close results, as the fragmentation of the vote means some candidates will win with less than a third of the vote. So, some say, this is the most unpredictable election… ever!
Haven’t we heard much of this before? Wasn’t the two-party system under attack in 2015? Weren’t there big changes in vote intention during the campaign in 2017, and 2010 for that matter? So is this really the most unpredictable election ever? Yes, yes, yes and no.
For an election to be predictable we need to have confidence in a forecasting method with sufficient accuracy. What is sufficient depends on what’s being asked. For the most crucial question of who gets to govern, more precision will be needed if the election is close. Conversely, it doesn’t matter much to most people if forecasters get the scale of a landslide wrong, so long as they identify the right party winning big.
In that sense we can’t (yet) predict the outcome of this election with much confidence. The Conservative lead over Labour in the polls is narrower than what it was at the same stage before the 2017 election. A lot changed in the final month last time, so we can’t rule out the possibility that opinion will change dramatically before polling day. That’s not to say that we should expect the same pattern of change, or any change at all. But many voters have already switched their votes and vote intentions at some point since 2017. Even if nothing changes between now and election day, this will still—by the traditional measure of change since the last election—be one of the most volatile elections on record.
Many pundits were overconfident about the chances of a Tory landslide in 2017. They are not making the same mistake again. But that’s not much protection against making a different mistake; it could even raise the risk of that.