Issues in Presidential Election Forecasting: Election Margins, Incumbency, and Model Credibility

Abstract

Three issues of presidential election forecasting research are raised. The first concerns the consequences for forecasting models of presidential elections becoming more narrowly decided. A realigned and polarized party system has led to smaller election margins in presidential contests since 1984. This development complicates model estimation and may also have blurred differences between strong and weak forecasting models. The second issue concerns the presidential incumbency advantage. Forecasting research has shed greater light on this important electoral factor. The advantage of presidential incumbency appears to be largely restricted to first party-term incumbents. This exposes what might be seen as a blind spot to electoral accountability. Finally, the issue of forecast model credibility is raised. Several criteria beyond forecast accuracy should be taken into account in assessing whether a forecast model and its prediction are credible.