Combining Forecasts for U.S. Presidential Elections: The Pollyvote

Posted: 9 Aug 2010

See all articles by Andreas Graefe

Andreas Graefe

Macromedia University of Applied Sciences

Alfred G. Cuzan

University of West Florida

Randall J. Jones

University of Central Oklahoma

J. Scott Armstrong

University of Pennsylvania - Marketing Department

Date Written: January 1, 2009

Abstract

In the PollyVote, we evaluated the combination principle to forecast the five U.S. presidential elections between 1992 and 2008. We combined forecasts from three or four different component methods: trial heat polls, the Iowa Electronic Markets (IEM), quantitative models and, in the 2004 and 2008 contests, periodic surveys of experts on American politics. The forecasts were combined within as well as across components. On average, combining within components reduced forecast error – and increased predictive accuracy – by 17% to 40%. Combining across components led to additional error reductions ranging from 7% to 68%, depending on the forecast horizon. In addition, across all five elections, the PollyVote predicted the correct election winner on all but 4 out of 957 days. The gains from applying the combination principle to election forecasting were much larger than those obtained in other fields.

Suggested Citation

Graefe, Andreas and Cuzan, Alfred G. and Jones, Randall J. and Armstrong, J. Scott, Combining Forecasts for U.S. Presidential Elections: The Pollyvote (January 1, 2009). Available at SSRN: https://ssrn.com/abstract=1656059

Andreas Graefe

Macromedia University of Applied Sciences ( email )

Sandstrasse 9
Munich, Bavaria 80337
Germany

HOME PAGE: http://www.andreas-graefe.org

Alfred G. Cuzan

University of West Florida ( email )

11000 University Parkway
Pensacola, FL 32514-5750
United States

Randall J. Jones

University of Central Oklahoma ( email )

100 North University Drive
Edmond, OK 73034
United States

J. Scott Armstrong (Contact Author)

University of Pennsylvania - Marketing Department ( email )

700 Jon M. Huntsman Hall
3730 Walnut Street
Philadelphia, PA 19104-6340
United States
215-898-5087 (Phone)
215-898-2534 (Fax)

HOME PAGE: http://marketing.wharton.upenn.edu/people/faculty/armstrong.cfm

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