Abstract
The issuance of forecasts in probabilistic terms introduces the problem of the measurement of the forecasting skill which goes into the preparation of this type of forecast. The applicability of the conventional skill score to the evaluation of probability forecasts is investigated. It is shown that the skill score can be generalized to give the amount of skill involved in the issuance of forecasts at the various probability levels. The conclusions reached throw some light on the use of the skill score when applied to the conventional two-category type of forecast.