Table 3 Statistical variables of the performance of a binary classification test
Acronym | Full name | Definition/Formula |
|---|---|---|
TP | True positive | Toxic compounds predicted as toxic |
TN | True negative | Non toxic compounds predicted as non toxic |
FP | False positive | Non toxic compounds predicted as toxic |
FN | False negative | Toxic compounds predicted as non toxic |
FP% | False positive rate | Ratio of non toxic compounds incorrectly classified as toxic FP/(FP + TN) |
FN% | False negative rate | Ratio of toxic compounds incorrectly classified as non toxic FN/(FN + TP) |
Sensitivity | Sensitivity or true positive rate | Ratio of toxic compounds correctly classified as toxic TP/(TP + FN) |
Specificity | Specificity or true negative rate | Ratio of non toxic compounds correctly classified as non toxic TN/(FP + TN) |
Accuracy | Accuracy or concordance | Proportion of the total number of predictions that were correct (TP + TN)/(TP + TN + FP + FN) |
PPV | Positive predictive value | Ratio of the predicted toxic compounds that were correct TP/(TP + FP) |
NPV | Negative predictive value | Ratio of the predicted non toxic compounds that were correct TN/(TN + FN) |