Levels of Evidence | Strength of Recommendation | ||
---|---|---|---|
I | Metaanalyses, systematic reviews of RCT, or individual RCT | A | Strong recommendation:
|
II | Metaanalysis, systematic reviews of observational studies (cohort/case control studies), or individual observational studies | B | Moderate recommendation:
|
OR | |||
RCT subgroup/post-hoc analyses | |||
III | Nonanalytic studies, e.g., case reports, case series | C | Weak recommendation
|
IV | Expert opinion | D | Consensus recommendation:
|
NR | Recommendations are not linked to evidence |
RCT: randomized controlled trial; NR: not reported.