ABSTRACT
This chapter is about the treatment of disease and draws particularly on one of the tools for the clinician to use when appraising the literature: using natural numbers or keeping the denominator constant. It discusses depression, sore throat, and colorectal cancer, setting out what doctors do in the consulting room against what’s happening among our entire patient population. Finding out what has prompted the patient in front of the doctor to consult unlike the others in the community who have not consulted is important. If the author asked members of the public, closed questions about symptoms, 23% would report at least one physical, mental or behavioural symptom in the previous two weeks for which they didn’t seek professional advice. Doctors use their understanding of the natural history of disease to weigh the probability and consequences of missing or delaying diagnosis against the probability and consequences of harming someone with a different disease or no disease at all.
