Class/Level/Strength of Evidence.24,25
| Class of Evidence | Study Designs |
|---|---|
| I=Strong evidence | Good quality (well designed), randomized clinical trial* |
| II=Moderate evidence | Moderate quality RT Good quality cohort study (CS) Good quality case control study (CCS) |
| III=Weak evidence | Poor quality RCT Moderate/poor quality CS or CCS Case Series, case reports, anatomical studies, expert opinion |