 For all these reasons, the EBM principle that treatment decisions should be based on the best available evidence from systematic research does not come out of nowhere. If, say, there is an RCT or an observational study that reports that treatment X is more effective at relieving symptoms S than treatment Y, it would seem bad to recommend a patient who suffers from S to take Y because his GP doesn’t know about X, doesn’t know the study result, personally profits from prescribing Y or is inattentive. However, while these are all bad reasons to recommend Y over X in the light of the study result, there may be a variety of good reasons.