Grade | Recommendation | Quality of Evidence |
---|---|---|
A | Strong | A preponderance of level I studies, but least 1 level I study directly on the topic support the recommendation. |
B | Moderate | A preponderance of level II studies but at least 1 level II study directly on topic support the recommendation. |
C | Weak | A single level II study at less than 25% critical appraisal score or a preponderance of level III and IV studies, including statements of consensus by content experts support the recommendation. |
D | Theoretical/foundational | A preponderance of evidence from animal or cadaver studies, from conceptual/theoretical models/principles, or from basic science/bench research, or published expert opinion in peer-reviewed journals supports the recommendation. |
P | Best practice | Recommended practice based on current clinical practice norms, exceptional situations where validating studies have not or cannot be performed and there is a clear benefit, harm, or cost, and/or the clinical experience of the guideline development group. |
R | Research | There is an absence of research on the topic, or higher-quality studies conducted on the topic disagree with respect to their conclusions. The recommendation is based on these conflicting or absent studies. |