Table 8.

Confusion matrix formulas.

Measure	Formula	Intuitive meaning
Precision (P)	TP / (TP + FP)	The percentage of positive predictions those are correct.
Recall / Sensitivity (R)	TP / (TP + FN)	The percentage of positive labeled instances that were predicted as positive.
Accuracy (A)	(TP + TN) / (TP + TN + FP + FN)	The percentage of predictions those are correct.
Error (E)	1-Accuracy	The percentage of predictions those are incorrect.
Macro-average	${\sum }_{i=1}^c{P}_i∕c$ “for Precision”	The average of the precision and recall of the system on different c classes.
	${\sum }_{i=1}^c{R}_i∕c$ “for Recall”
Micro-average	(TP1 + TP2) / (TP1 + TP2 + FP1 + FP2) “for precision”	The summation up to the individual true positives, false positives, and false negatives of the system for different classes and the apply them to get the statistics
	(TP1 + TP2) / (TP1 + TP2 + FN1 + FN2) “for Recall”
F-measure	2*PR/(P+R)	The weighted harmonic mean of Precision and Recall