Membrane -As a proxy for a generic off-target assay, a random forest classification model at a 10 µM concentration for every Class A GPCR targets with sufficient bioactivity data in ChEMBL31 is run (266 out of a possible 312). The prediction is classified into active or inactive (as opposed to taking the predicted probability) for each receptor and the ratio of active predictions is returned as the score. This ratio is transformed so that low ratios have a high score, therefore minimising this parameter. The arithmetic mean is taken in combination with the predicted probability of activity against 5-HT2A.