Alan Cassels is the author of the recently published Seeking Sickness: Medical Screening and the Misguided Hunt for Disease, and is currently writing a social history of The Cochrane Collaboration. Here he presents the essential differences – with illustrative examples – between ‘eminence-based medicine’ and ‘evidence-based medicine’.

What is ‘eminence-based medicine’? It means relying on the opinion of a medical specialist or other prominent health official when it comes to health matters, rather than relying on a careful assessment of relevant research evidence. You might be asking, “Who am I to question an ‘expert’, especially a physician, a specialist or a prominent medical researcher who knows so much more than me?” Here are a few recent examples of eminence-based medicine in the real world, which hopefully will leave you questioning . . . more.