Table 1 GRADE quality assessment criteria
Study design | Initial quality of a body of evidence | Quality of evidence | Lower if | Higher if |
|---|---|---|---|---|
RCT | High | High | Risk of Bias | Large effect |
| Ā | Moderate | -1 Serious | ā+ā1 Large | |
| Ā | low | -2 Very serious | ā+ā2 Very large | |
| Ā | Extremely low | Inconsistency | Dose response | |
| Ā | Ā | -1 Serious | ā+āEvidence of a gradient | |
| Ā | Ā | -2 Very serious | All plausible residual confounding | |
| Ā | Ā | Indirectness | ā+ā1 Would reduce a demonstrated effect | |
| Ā | Ā | -1 Serious | ā+ā1 Would suggest a spurious effect if no effect was observed | |
| Ā | Ā | -2 Very serious | Ā | |
| Ā | Ā | Publication bias | Ā | |
| Ā | Ā | -1 Likely | Ā | |
| Ā | Ā | -2 Very likely | Ā |