Published online by Cambridge University Press: 08 January 2009
The October 2008 issue of PS published a symposium of presidential and congressional forecasts made in the summer leading up to the election. This article is an assessment of the accuracy of their models.
The Time-for-Change Model proved one of the most accurate of the 2008 presidential election forecasts run in the October PS symposium. Using three predictors—the president's approval rating at mid-year, the growth rate of real GDP during the second quarter, and the time-for-change dummy variable—the model predicted that Barack Obama would win the presidential election with 54.3% of the major-party vote. According to nearly final tabulations compiled by uselections.org, as of December 8, Obama has received just over 53.6% of the major-party vote. However, it is likely that Obama's final total will reach 53.7% of the major-party vote. Therefore, the model's current error of 0.9 percentage points is likely to decrease further. The model has now correctly predicted the winner of the popular vote in all six presidential elections since its creation in 1988.