Forecasting the 2015 British general election: The 1992 debacle all over again?

This article introduces and reviews a set of twelve academic forecasts of the 2015 British general election. Along with the vast majority of others including journalists and betting markets, they failed by a big margin to predict that the Conservatives would emerge with an overall majority of seats. Several suffered from the 1992 scale inaccuracies of the vote-intention opinion polls. Forecasts based on other data sources typically did a bit better, but also fell short. Nonetheless, this was not 1992 all over again. The dramatic collapse of the Liberal Democrats and rise of the SNP, UKIP and Greens were successfully anticipated. Also this collection includes numerous methodological advancements, with several new methods and developments to established approaches.