Brief Reports

Journal of General Internal Medicine

, Volume 17, Issue 8, pp 647-650

First online:

Simplifying likelihood ratios

  • Steven McGeeAffiliated withUniversity of Washington Seattle-Puget Sound VA Health Care System (S-111 GIMC) Email author 

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Likelihood ratios are one of the best measures of diagnostic accuracy, although they are seldom used, because interpreting them requires a calculator to convert back and forth between “probability” and “odds” of disease. This article describes a simpler method of interpreting likelihood ratios, one that avoids calculators, nomograms, and conversions to “odds” of disease. Several examples illustrate how the clinician can use this method to refine diagnostic decisions at the bedside.

Key words

likelihood ratio diagnostic accuracy