- An informal survey among colleagues turns up the far-from surprising information that the average patient contact involves at least three or four judgements and decisions: judgements about aetiology and prognosis, decisions about diagnosis and therapy, and sometimes discussions about costs and side-effects. And so it goes: 20 patients a day, 60 decisions; 100 patients a week, 300 decisions. Who makes these decisions, the doctor or the patient? What factors govern the final choice in each case? Evidence-based medicine (EBM) is the factor getting a lot of attention these days, but clinical decisions depend on many different elements. Good doctors have always made use of experience and judgement as well as the best available evidence.