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Sackett’s Levels of Evidence
| Level of Evidence | General criteria for LOE |
|---|---|
| I | Single high-quality randomized, controlled trial (RCT) or systematic review of homogenous RCTs |
| II | Single cohort study, low-quality RCT (i.e. less than 80% follow-up), or systematic review of cohort studies |
| III | Case-control studies |
| IV | Case series, low-quality cohort and case-control studies |
| V | Expert opinion without critical appraisal |
