A |
Strong evidence |
A preponderance of level I and/or level II studies support the recommendation. This must include at least 1 level I study |
B |
Moderate evidence |
A single high-quality randomized controlled trial or a preponderance of level II studies support the recommendation |
C |
Weak evidence |
A single level II study or a preponderance of level III and IV studies including statements of consensus by content experts support the recommendation |
D |
Conflicting evidence |
Higher-quality studies conducted on this topic disagree with respect to their conclusions. The recommendation is based on these conflicting studies. |
E |
Theoretical/foundational evidence |
A preponderance of evidence from animal or cadaver studies, from conceptual models/principles or from basic sciences/bench research support this conclusion |
F |
Expert opinion |
Best practice based on the clinical experience of the guidelines development team |