Relative Merits of Different Ways of Combining Judgment with Statistical Forecasts

Instead of using your judgment to combine judgmental and statistical forecasts, just average them. Also, using your judgment to adjust a statistical forecast is better than modifying your judgmental forecast on the basis of a statistical one. Judgmental adjustment is likely to be more successful if you are a domain expert, if you use decomposition, if more than one person estimates the size of the required adjustment , if you have knowledge not used in the statistical forecast, and if you keep records that allow you to see whether your past adjustments have been too large or too small. Copyright International Institute of Forecasters, 2005