Forecasting the outcome of a national election: the influence of expertise, information, and political preferences

Abstract

"Five days in advance of the 2005 German national election, political experts, voters, and novices were asked to predict the outcome of the election. In an experimental manipulation, half of the non-expert sample was provided with additional poll information in the form of a figure with trend lines. The results show that (1) experts were marginally more accurate than non-experts but highly overconfident in their predictions, that (2) access to pre-election poll information improved the forecasting ability of novices, and that (3) partisan preferences biased the forecasts of voters to a small degree (projection effect)." (author's abstract)