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. Author manuscript; available in PMC: 2011 Aug 21.
Published in final edited form as: J Orthop Sports Phys Ther. 2010 Apr;40(4):A1–A37. doi: 10.2519/jospt.2010.0303
GRADES OF RECOMMENDATION BASED ON STRENGTH OF EVIDENCE
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