Framework to classify review level evidence
| Sufficient review level evidence to either support or discount the effectiveness of an intervention |
| Clear and consistent statement from one or more core reviews based on multiple robust studies, or |
| Consistent evidence across multiple robust studies within one or more core reviews, in the absence of a clear and consistent statement in the review(s) |
| Tentative review level evidence to either support or discount the effectiveness of an intervention |
| A cautious statement from one or more core reviews based on consistent evidence from a small number of robust studies, or |
| Consistent evidence from a small number of robust studies or multiple weaker studies within one or more core reviews, in the absence of a clear and consistent statement in the review(s), or |
| Conflicting evidence from one or more core reviews, with the stronger evidence weighted towards one side (either supporting or discounting effectiveness) and a plausible reason for the conflict, or |
| Consistent evidence from multiple robust studies within one or more supplementary review, in the absence of a core review |
| Insufficient review level evidence to either support or discount the effectiveness of an intervention |
| A statement of insufficient evidence from a core review, or |
| Insufficient evidence to either support or discount the effectiveness of an intervention (either because there is too little evidence or the evidence is too weak), in the absence of a clear and consisten statement of evidence from a core review(s), or |
| Anything less than consistent evidence from multiple robust studies within one or more supplementary reviews. |
| No review level evidence |
| No core or supplementary reviews of the topic identified, possibly due to a lack of primary studies |