Published online by Cambridge University Press: 08 January 2009
The October 2008 issue of PS published a symposiumof presidential and congressional forecasts made in the summerleading up to the election. This article is an assessment of theaccuracy of their models.
The Time-for-Change Model proved one of the most accurate of the 2008presidential election forecasts run in the OctoberPS symposium. Using three predictors—thepresident's approval rating at mid-year, the growth rate of real GDPduring the second quarter, and the time-for-change dummyvariable—the model predicted that Barack Obama would win thepresidential election with 54.3% of the major-party vote. Accordingto nearly final tabulations compiled by uselections.org, as ofDecember 8, Obama has received just over 53.6% of the major-partyvote. However, it is likely that Obama's final total will reach53.7% of the major-party vote. Therefore, the model's current errorof 0.9 percentage points is likely to decrease further. The modelhas now correctly predicted the winner of the popular vote in allsix presidential elections since its creation in 1988.