ORGANIZA’fIONAL BEIWVIOR AN11 HUMAN DECISION PROCESSES

The accuracy of judgmental forecasts of temperature and precipitation was analyzed. In contrast to the findings of many studies of expert judgment and forecasting, forecasts were highly accurate and forecaster agreement was high. Human forecasters performed better than an operational forecasting model and about the same as a linear regression model. Differences between temperature and precipitation forecasts could be predicted from differences between the tasks. In general, differences between tasks were much greater than differences between forecasters. Task predictability was an excellent indicator of forecast accuracy. The characteristics of the environment for forecasting temperature and precipitation that contribute to accuracy include high-quality information and the availability of “guidance” based on a computer model. It is concluded that an understanding of the properties of the task is essentiaI for understanding the accuracy of expert judgment. o 1997 Academic Press