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.
In summer 2008, our Jobs Model forecast a Democratic presidential candidate two-party popular vote share of 56.6%, which would deliver the incumbent party the biggest defeat of any post-World War II contest (Lewis-Beck and Tien 2008). However, we argued, from our analysis of different experimental and observational evidence, that this unprecedented victory would be prevented by racially intolerant voters. We estimated the net racial cost of being a black candidate and corrected our overall forecast downward to 50.1% for Barack Obama. The unparalleled economic crisis, initiated after the release of our summer forecasts, prompted a reconsideration; the unique shock to the economy was no ordinary campaign perturbation. We calculated that the ensuing boost to anti-incumbent economic voting would add approximately two percentage points to the opposition; therefore, we issued a public revision of our forecast to 52.0 % for Obama (Lewis-Beck 2008). We are pleased that this final forecast fell so close to the actual result of 53.5%. Nevertheless, we contend the actual result should have been much closer to our original forecast. Given the dismal state of the polity and the economy prior to the election, the Obama victory should have been much bigger, as we show below.