Analysis of Battleground State Presidential Polling Performances, 2004–2012

This article explores the performance of major political polls as reported on a well-known political website. The presidential elections of 2004, 2008, and 2012 are examined, and polling results for battleground states are compared to the actual margins in each state. These data are combined into an analysis of variance (ANOVA) model and differences in the various polls assessed. No significant differences in polls were found in 2004 or 2008. In contrast, very large differences were found in 2012, and all polls were found to underestimate President Obama’s performance in the battleground states. In addition to individual polling results, a model using the statewide and national polling data from all polls is created. These results are compared to the established polls. We present a possible explanation as to why the polls in the recent (2012) election are all biased toward the Republican side.