Je. Campbell, POLLS AND VOTES - THE TRIAL-HEAT PRESIDENTIAL-ELECTION FORECASTING-MODEL, CERTAINTY, AND POLITICAL CAMPAIGNS, American politics quarterly, 24(4), 1996, pp. 408-433
This article revises, updates, and examines the background for a highl
y accurate model for forecasting the national two-party popular vote i
n presidential elections. The model provides a vote prediction in earl
y September based on Gallup trial-heat or presidential preference poll
s and the (nonannualized) rate of economic growth in the second quarte
r of the election year. It is estimated over the 12 presidential elect
ions from 1948 to 1992. The mean absolute error of the model's out-of-
sample postdictions is less than 1 1/3 percentage point, and its actua
l error in predicting the 1992 vote was about half a percentage point.
The article also assesses the reasons for confidence in the model, as
well as an approach to gauging uncertainty in any specific forecast.
The reasons presidential elections can be forecast at or before the be
ginning of the general election campaign also are explored. Finally, t
he forecasting model is applied to the 1996 presidential campaign betw
een Clinton and Dole.