Table 1 Grading of evidence
Grading of evidence | ||
|---|---|---|
Category of evidence | Grading of evidence | |
Traditional | Guideline | |
Meta-analysis of randomized controlled trials | Ia | A |
Randomized controlled trials | Ib | A |
Well-designed and controlled study without randomization | IIa | B |
Well-designed quasi-experimental study | IIb | B |
Nonexperimental descriptive study | III | B |
Expert opinion | IV | C |
