What are precision and recall?

Precision is the proportion of true positives out of predicted positives. To put it in another way, it is the accuracy of the prediction. It is also known as the ‘positive predictive value’.

Precision = \frac{TP}{(TP + FP)}

Recall is the same as the true positive rate (TPR) or the sensitivity. 

Recall = \frac{TP}{TP+FN}