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Criteria for rating the quality of evidence for individual studies
| Level of Evidence | Description |
|---|---|
| 1 = Strong | Systematic review/meta-analysis of RCTs with consistent findings; high-quality individual RCT |
| 2 = Medium | Systematic review/meta-analysis of lower-quality clinical trials or of studies with inconsistent findings; lower quality clinical trial; cohort study; case–control study |
| 3 = Weak | Consensus guidelines; usual practice; expert opinion; case series |
