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Accuracy of Combined Forecasts for the 2012 Presidential Election: The PollyVote

Published online by Cambridge University Press:  14 April 2014

Andreas Graefe
LMU Munich
J. Scott Armstrong
University of Pennsylvania and University of South Australia
Randall J. Jones Jr.
University of Central Oklahoma
Alfred G. Cuzán
University of West Florida


We review the performance of the PollyVote, which combined forecasts from polls, prediction markets, experts’ judgment, political economy models, and index models to predict the two-party popular vote in the 2012 US presidential election. Throughout the election year the PollyVote provided highly accurate forecasts, outperforming each of its component methods, as well as the forecasts from Gains in accuracy were particularly large early in the campaign, when uncertainty about the election outcome is typically high. The results confirm prior research showing that combining is one of the most effective approaches to generating accurate forecasts.

Copyright © American Political Science Association 2014 

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