Who will turnout and who will not? The indicator that could make or break GE2017 poll predictions

Why do polling predictions for the UK’s general election vary so widely? Patrick Sturgis and Will Jennings argue that turnout might prove the be the pollsters’ Achilles heel in this occasion. Getting its weighting right is likely to be both more difficult and more consequential than it was in 2015, because the age gap in party support has increased since the last election.