Definition of Levels of Evidence and Strength of Recommendation (Adapted From Andrews et al10)
| Level of evidence | |
|---|---|
| High | At least one RCT or SR/meta-analysis with no concerns regarding study quality |
| Moderate | At least one RCT or SR/meta-analysis with minor concerns regarding study quality or, at least one cohort/case-control/diagnostic test design study with no concerns regarding study quality |
| Low | At least one cohort/case-control/diagnostic test study with minor concerns regarding study quality, or at least one single arm before-after study or cross-sectional study with no concerns regarding study quality |
| Very low | At least one cohort/case-control/diagnostic test design study with serious concerns regarding study quality, or at least one single arm before-after study or cross-sectional study with minor/severe concerns regarding study quality |
| Grade of recommendation | |
|---|---|
| Strong for | Strong recommendations are offered when the desirable effects of an intervention clearly outweigh the undesirable effects |
| Conditional for | Conditional recommendations are offered when trade-offs are less certain, either because of low-quality evidence or because evidence suggests that desirable and undesirable effects are closely balanced |
RCT, randomized controlled trial; SR, systematic review.