The aim of these reflections on uncertainty in medicine is not to discredit evidence-based medicine or to incite suspicion of the careful and caring processes by which most clinicians arrive at the advice they give.  Rather it is to change conversations among practitioners and between them and their patients in such a way as to raise everyone’s tolerance for the inevitable ambiguities and uncertainties we live with.  If the public were more aware of the basic rules of mathematical probabilities, how statisticians understand the term “significance,” and of how much changes when one new variable is taken into account—when a new medication with multiple possible side-effects is added to the mix, for instance—they might, Hatch argues, be less inclined to insist on specific predictions.  He goes on to suggest that there is something to be gained from the challenge of living without the solid ground of assurances.  When we recognize the need to make decisions with incomplete information (a condition that seems, after all, to be our common lot) we may refocus on the moment we’re in and see its peculiar possibilities. Changing the conversation requires a critical look at medical education which, Hatch observes, “measures a certain type of knowledge essential to medical practice, but it consequently engenders a conception of medicine best described as overly certain . . . .” 


Despite the doubt it casts on the language of certainty that often overstates, Snowball in a Blizzard is an oddly encouraging book.  Honesty between doctors and patients about what can’t be known may be unsettling, but it can yield actual benefits in quality of care.  Part of clinical work is education, and thoughtfully informed patients, if they are willing to confront ambiguities and uncertainties, are likely to make better decisions.  So Hatch’s argument goes, and he makes it with care, convincing examples, and arguments from probability theory and statistics that make it clear that his aim is to educate and empower the public to be full and informed participants in medical deliberation.  A very readable and worthwhile read for clinicians and the public alike.


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