INCUMBENCY, NATIONAL CONDITIONS, AND THE 2008 PRESIDENTIAL ELECTION

In: PS: political science & politics, Volume 42, Issue 1, p. 22-22

Abstract

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 Incumbency and National Conditions Model predicted that John
McCain would receive 44.3% of the two-party presidential vote; he
ended up with 46.6% (at this writing, November 13, 2008), yielding a
prediction error of 2.4 points. This error is slightly smaller than
the mean absolute value of the out-of-sample forecasts from 1952 to
2004 (2.68), so the 2008 election result is not anomalous in the
context of this model. The addition to the model of the 2008 outcome
does not generate many important changes to the coefficients, except
that the significance of incumbency interaction went from 0.08 to
0.02 and the standard error and adjusted R2 of the model
both indicate a slight improvement in fit.