Risk of bias | Across studies | Interpretations | Considerations | GRADE assessment |
---|---|---|---|---|
Low risk of bias. | Most information is from studies at low risk of bias. | Plausible bias unlikely to seriously alter the results. | No apparent limitations. | No serious limitations, do not downgrade. |
Unclear risk of bias. | Most information is from studies at low or unclear risk of bias. | Plausible bias that raises some doubt about the results. | Potential limitations are unlikely to lower confidence in the estimate of effect. | No serious limitations, do not downgrade. |
Potential limitations are likely to lower confidence in the estimate of effect. | Serious limitations, downgrade one level. | |||
High risk of bias. | The proportion of information from studies at high risk of bias is sufficient to affect the interpretation of results. | Plausible bias that seriously weakens confidence in the results. | Crucial limitation for one criterion, or some limitations for multiple criteria, sufficient to lower confidence in the estimate of effect. | Serious limitations, downgrade one level |
Crucial limitation for one or more criteria sufficient to substantially lower confidence in the estimate of effect. | Very serious limitations, downgrade two levels. |