Strength of Recommendation Taxonomy (SORT):A Patient-Centered Approach to Grading Evidencein the Medical Literature Mark H. Ebell, MD, MS, Jay Siwek, MD, Barry D. Weiss, MD,Steven H. Woolf, MD, MPH, Jeffrey Susman, MD, Bernard Ewigman, MD, MPH, andMarjorie Bowman, MD, MPA A large number of taxonomies are used to rate the quality of an individual study and the strength of arecommendation based on a body of evidence. We have developed a new grading scale that will be usedby several family medicine and primary care journals (required or optional), with the goal of allowingreaders to learn one taxonomy that will apply to many sources of evidence. Our scale is called theStrength of Recommendation Taxonomy. It addresses the quality, quantity, and consistency of evidenceand allows authors to rate individual studies or bodies of evidence. The taxonomy is built around theinformation mastery framework, which emphasizes the use of patient-oriented outcomes that measurechanges in morbidity or mortality. An A-level recommendation is based on consistent and good qualitypatient-oriented evidence; a B-level recommendation is based on inconsistent or limited quality patient-oriented evidence; and a C-level recommendation is based on consensus, usual practice, opinion,disease-oriented evidence, or case series for studies of diagnosis, treatment, prevention, or screening.Levels of evidence from 1 to 3 for individual studies also are defined. We hope that consistent use ofthis taxonomy will improve the ability of authors and readers to communicate about the translation ofresearch into practice. (J Am Board Fam Pract 2004;17:59 – 67.)