EVALUATING PROBABILITY FORECASTS.

Abstract : The accuracy of an aggregate of probability forecasts involves two basic attributes which are called reliability and sharpness. By expanding the equation of the Brier-Allen Probability Score, consistent definitions of reliability and sharpness are derived in which the correlation coefficient between forecasts and outcomes has a key role. Presented is a graphic means of comparing aggregates of probability forecasts in terms of their reliability and sharpness. (Author)