Score Definitions

Mean Absolute Error (MAE)

MAE definition: the summation of absolute value of ( each forecast minus observation ) divided by number of cases. A higher MAE represents less accuracy. A continuous variable.

 

 

Mean Algebraic Error (Bias)

Bias definition: the summation of ( each forecast minus observation ) divided by number of cases. A positive value represents a warm or wet bias. A negative value represents a cool or dry bias.  A continuous variable.

 

 

Brier Score

brier score definition: the summation of ( each forecast minus observation )squared, divided by number of cases. A forecast is a probability between 0 and 1. Observation of 1 means an event occurred, 0 means it did not. A probability score.

 

 

Heidke Skill Score (HSS)

Heidke Skill Score definition:  number of hits minus expected hits by chance divided by total number of cases minus expected number of his by chance. A categorical variable.

 

 

Probability of Detect (POD), False Alarm Ratio (FAR), and Threat Score

Probability of Detection, False Alarm Ratio and Threat Score Definitions: Threat Score: Probability of Detection (POD): number of correct forecasts of event divided by number of observed events.  False Alarm Ratio: number of incorrect forecasts of event divided by number of forecasts of event. Threat Score: number of correct forecasts of event divided by number of forecasts and/or observations of event. All three are categorical variables.

 

MOS