Forecast skill

Forecast skill (or skill score, forecast skill, prediction skill), in the fields of forecasting and prediction, is any measure of the accuracy and/or degree of association of prediction to an observation or estimate of the actual value of what is being predicted (formally, the predictand). Forecast skill (or skill score, forecast skill, prediction skill), in the fields of forecasting and prediction, is any measure of the accuracy and/or degree of association of prediction to an observation or estimate of the actual value of what is being predicted (formally, the predictand). In meteorology, forecast skill in weather forecasting, a motivating application, measures the superiority of a forecast over a simple historical baseline of past observations. The same forecast methodology can result in different skill measurements at different places, or even in the same place for different seasons (e.g. spring weather might be driven by erratic local conditions, whereas winter cold snaps might correlate with observable polar winds). Forecast skill is often presented in the form of seasonal geographical maps. Forecast skill for single-value forecasts is commonly represented in terms of metrics such as correlation, root mean squared error, mean absolute error, relative mean absolute error, bias, and the Brier score, among others. A number of scores associated with the concept of entropy in information theory are also being used.