Revised grading system for recommendations in evidence based guidelines

Strength of Recommendation and Quality of Evidence

Category/grade Definition

Strength of recommendation

A Good evidence to support a recommendation for or against use.

B Moderate evidence to support a recommendation for or against use.

C Poor evidence to support a recommendation.

Quality of evidence

I Evidence from >1 properly randomized, controlled trial.

II Evidence from >1 well-designed clinical trial, without randomization; from cohort or case-controlled

analytic studies (preferably from .1 center); from multiple time-series; or from dramatic

results from uncontrolled experiments.

III Evidence from opinions of respected authorities, based on clinical experience, descriptive

studies, or reports of expert committees.