Comparison of Objective and Subjective Precipitation Probability Forecasts: The Sufficiency Relation

Abstract In this paper the sufficiency relation is used to compare objective and subjective probability of precipitation (PoP) forecasts. The theoretical significance of the sufficiency relation in comparative evaluation arises from the fact that if it can be shown that forecasting system A is sufficient for forecasting system B, then A's forecasts are necessarily of higher quality and greater value to all users than B's forecasts. However, since the sufficiency relation is an incomplete order (it is not always possible to show that system A is sufficient for system B, or vice versa), the practical significance of this relation warrants further investigation. An operational method of comparing forecasting systems using the sufficiency relation has recently been described in the forecasting literature. This method involves the construction of a so-called forecast sufficiency characteristic (FSC) for each forecasting system, based on a representative set of forecasts and observations. In terms of this chara...