Basic Terms

• FN: False Negative (type II error, miss, understimation)
• FP: False Positive (type I error, false alarm, overestimation)
• N: Actual Negative
• P: Actual Positive
• PN: Predicted Negative
• PP: Predicted Positive
• TN: True Negative
• TP: True Positive

Derived Terms

Prevalence

P / (P + N)

Accuracy

(TP + TN) / (P + N)

Positive Predictive Value (PPV)

TP / PP

Negative Predictive Value (NPV)

TN / PN

False Discovery Rate (FDR)

FP / PP

False Omission Rate (FOR)

FN / PN

True Positive Rate (TPR)

Probability of detection, hit rate.

TP / P

False Positive Rate (FPR)

Probability of a false alarm

FP / N

False Negative Rate (FNR)

Miss rate

FN / P

True negative rate (TNR)

Specificity

TN / N

References

• Wikipedia | Sensitivity and Specificity