Statistical Measures for Diagnostic Accuracy
Name | Acronym | Formula |
Positive predictive value | PPV | TP/(TP + FP) |
Negative predictive value | NPV | TN/(TN + FN) |
Positive likelihood ratio | PLR | [TP/(TP + FN)]/[FP/(FP + TN)] |
Negative likelihood ratio | NLR | [FN/(TP + FN)]/[TN/(FP + TN)] |
Sensitivity or rate of TP results | TPR | TP/(TP + FN) |
Specificity or rate of TN results | TNR | TN/(TN + FP) |
Conventional accuracy | CA | (TP + TN)/(TP + FP + FN + TN) |
Balanced accuracy | BA | [TP/(TP + FN) + TN/(TN + FP)]/2 |
Discordance of accuracies | DA | |CA − BA| |
All measures except DA were expressed in terms of numbers of TP, FP, TN, and FN results.