Table 2 Grading of Recommendations Assessment, Development and Evaluation system. Adapted from Guyatt et al. 2008 [31]
Grading | Publication type | Recommendations |
|---|---|---|
High quality | Meta-analyses, systematic reviews of RCTs, or RCTs with a low risk of bias | Further research is very unlikely to change our confidence in the estimate of effect |
Moderate quality | High quality systematic reviews of case control or cohort studies; High quality case control or cohort studies with a very low risk of confounding or bias and a high probability that the relationship is causal; Well-conducted case control or cohort studies with a low risk of confounding or bias and a moderate probability that the relationship is causal | Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate |
Low quality | Case control or cohort studies with a high risk of confounding or bias and a significant risk that the relationship is not causal | Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate |
Very low quality | Non-analytic studies, e.g. case reports, case series; Expert opinion | Any estimate of effect is very uncertain |