Rating the Strength of Evidence


Evidence-based medicine is the conscientious, explicit, and judicious use of the current best evidence in making decisions about the care of individual patients. At American Family Physician, we ask authors to explicitly rate the strength of evidence supporting key recommendations on diagnosis and treatment whenever possible.

We realize there are various rating systems for levels of evidence described in the medical literature. Working with the editors of other leading primary care publications, we have developed a new system that rates the evidence from A to C. We ask that you use this system to rate key recommendations on diagnosis and treatment:

Strength of RecommendationDefinition
Strength of Recommendation: ADefinition: Recommendation based on consistent and good quality patient-oriented evidence
Strength of Recommendation: BDefinition: Recommendation based on inconsistent or limited quality patient-oriented evidence
Strength of Recommendation: CDefinition: Recommendation based on consensus, usual practice, expert opinion, disease-oriented evidence, and case series for studies of diagnosis, treatment, prevention, or screening

We expect that this system will encourage you to carefully consider the supporting documentation for the key recommendations you make. It may also prompt you to examine additional key sources of evidence-based recommendations, such as those outlined below. During the process of review and editing, our medical editors may ask you to rate certain statements according to this scale. If you have any questions about how to properly use it, please talk with the medical editor assigned to your manuscript.

Key Clinical RecommendationStrength of RecommendationReferencesComments (optional)
Key Clinical Recommendation: Ambulatory blood pressure monitoring is recommended for patients with labile blood pressure and suspected white coat hypertension.Strength of Recommendation: BReferences: 2Comments (optional): Recommendation from consensus guideline based on observational studies
Key Clinical Recommendation: Diuretics and beta-blockers are first-line agents for hypertension.Strength of Recommendation: AReferences: 3Comments (optional): Meta-analysis of randomized trials
Key Clinical Recommendation: Angiotensin receptor blockers provide similar clinical outcomes to ACE inhibitors.Strength of Recommendation: AReferences: 4,5,6Comments (optional): Consistent findings from randomized controlled trials and recommendation from evidence-based practice guideline
Key Clinical Recommendation: Terazosin is not recommended as a first or second line agent, particularly for black patients.Strength of Recommendation: AReferences: 7Comments (optional): Randomized controlled trial

In general, you should choose approximately three to seven key recommendations for your article. Do not choose statements that merely summarize research findings; choose important clinical recommendations that reflect the best available evidence. At a minimum, the summary table should include the recommendations and references. Comments to justify your choice of references are helpful to the editors.

For more information on how to apply these ratings, please see Strength of Recommendation Taxonomy (SORT): A Patient-Centered Approach to Grading Evidence in the Medical Literature, an explanatory article published in the February 1, 2004, issue of AFP, as well as the algorithm for rating the strength of evidence(2 page PDF). You should create a summary table with the recommendations and references for each recommendation.