Simple Rules for Combining Forecasts: Some Empirical Results

Abstract

This study is an empirical comparison of three rules for aggregating forecasts. The three combined forecasts evaluated are: a simple average forecast, a median forecast and a focus forecast. These combined forecasts are compared over four economic variables (housing starts, the index of industrial production, the unemployment rate and gross national product) using a set of previously published forecasts. The results indicate that an average forecast will not perform as well as previous studies indicate if all or most of the individual forecasts tend to over- or under-predict simultaneously. The median forecast also seems to be suspect in this case. There is little evidence to suggest that the median forecast is a viable alternative to the mean forecast. Focus forecasting, however, is found to perform well for all four variables. The evidence indicates that focus forecasting is a reasonable alternative to simple averaging.