Table 2 Grades of recommendation (reproduced with the permission of the SIGN group)
From: Effects of Tai Chi exercises on self-efficacy and psychological health
| Grades of recommendation | |
|---|---|
| 1++ | High quality meta-analyses, systematic reviews of RCTs, or RCTs with a very low risk of bias |
| 1+ | Well conducted meta-analyses, systematic reviews of RCTs, or RCTs with a low risk of bias |
| 1− | Meta-analyses, systematic reviews of RCTs, or RCTs with a high risk of bias |
| 2++ | High quality systematic reviews of case control or cohort or studies |
| High quality case-control or cohort studies with a very low risk of confounding, bias, or chance and a high probability that the relationship is causal | |
| 2+ | Well conducted case-control or cohort studies with a low risk of confounding, bias, or chance and a moderate probability that the relationship is causal |
| 2− | Case control or cohort studies with a high risk of confounding , bias, or chance and a significant risk that the relationship is not causal |
| 3 | Nonanalytic studies, e.g., case reports, case series |