Vote Expectations Versus Vote Intentions: Rival Forecasting Strategies

Abstract

Are ordinary citizens better at predicting election results than conventional voter intention polls? The authors address this question by comparing eight forecasting models for British general elections: one based on voters' expectations of who will win and seven based on who voters themselves intend to vote for (including 'uniform national swing model' and 'cube rule' models). The data come from ComRes and Gallup polls as well as the Essex Continuous Monitoring Surveys, 1950-2017, yielding 449 months with both expectation and intention polls. The large sample size permits comparisons of the models' prediction accuracy not just in the months prior to the election, but in the years leading up to it. Vote expectation models outperform vote intention models in predicting both the winning party and parties' seat shares.