Table 12.2.a: Levels of quality of a body of evidence in the GRADE approach
Underlying methodology |
Quality rating |
Randomized trials; or double-upgraded observational studies. |
High |
Downgraded randomized trials; or upgraded observational studies. |
Moderate |
Double-downgraded randomized trials; or observational studies. |
Low |
Triple-downgraded randomized trials; or downgraded observational studies; or case series/case reports. |
Very low |