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April 18, 2012

Risk Models and Patient-Centered Evidence: Should Physicians Expect One Right Answer?

Author Affiliations

Author Affiliations: Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, Massachusetts (Dr Kent); Division of Health Care Policy and Research, Mayo Clinic, Rochester, Minnesota (Dr Shah).

JAMA. 2012;307(15):1585-1586. doi:10.1001/jama.2012.469

All models are wrong, but some are useful.—George Box

A fundamental contradiction of evidence-based medicine (EBM) is that evidence is derived from groups, whereas medicine is applied to individuals. Inferring individual effects from average group effects is an example of the fallacy of division. Even in a randomized trial, benefit in a summary result does not imply that the probability of benefitting outweighs the risk of harm for all (or even most) patients within the trial.1