Abstract
This study compared meteorologists, an expert system, and simple weighted-sum models in a limited-information hail forecasting experiment. It was found that forecasts made by meteorologists were closely approximated by an additive model, and that the model captured most of their forecasting skill. Furthermore, the additive model approximated the meteorologists’ forecasts better than the expert system did. Results of this study am consistent with the results of extensive psychological research on judgment and decision making processes. Potential implications are discussed.