Fig. 3.

Sample selection for training and evaluation of three types of model (I–III). For type I models, we used 10–90% of all drug pairs positive for an ADR as the positive class for model training, with half of the other drug pairs in the TWOSIDES database used as the baseline class. We used the remaining drug pairs as a test set for assessing model performance. Sample selection for type II models was the same as that for type I models except that we moved half of the positive samples in the test set into the baseline class of the training set to provide known false negatives. Sample selection for type III models was the same as that for type I models except that some randomly selected baseline samples in the test set were moved into the positive class in the training set to provide false positives. The number of false positives was equal to the number of true positives in the training set