Table 3 Level of Evidence according to the Classification schemes
Level of Evidence: | |
|---|---|
Ia | Evidence for meta-analysis of randomized controlled trials |
Ib | Evidence from at least one randomized controlled trial |
IIa | Evidence from at least one controlled study without randomization |
IIb | Evidence from at least one other type of quasi-experimental study |
III | Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies, and case-control studies |
IV | Evidence from expert committee reports or opinions or clinical experience of respected authorities, or both |