Table 4 Definition of Grades of Recommendation for action statements

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.