Forecasting presidential elections using history and polls

We develop a method for efficiently using current poll data to update election forecasts based on historical relationships. The method is applied on an ex post basis to forecast Republican and Democratic shares of the national vote in US Presidential elections from 1952 to 1992. Using poll data substantially improves the performance of forecasting models that rely solely on historical fundamentals. Moreover, when poll data are used appropriately, their information content dominates in the calculation of an optimal forecast. The method has also been applied on an ex ante basis to forecast the 1996 presidential election, producing a series of highly accurate predictions over the 2 month period before the election.