Revised grading system for recommendations in evidence based guidelines
Strength of Recommendation and Quality of Evidence
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.