|
Ia |
Evidence obtained from meta-analysis or systematic reviews of randomized controlled trials. |
|
Ib |
Evidence obtained from at least one randomized controlled trial. |
|
IIa |
Evidence obtained from at least one well-designed controlled study without randomization. |
|
IIb |
Evidence obtained from at least one other type of well-designed quasi-experimental study, without randomization. |
|
III |
Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies and case studies. |
|
IV |
Evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities. |
Adapted from the Scottish Intercollegiate Guidelines Network (Scottish Intercollegiate Guidelines Network [SIGN], 2011) and Pati (2011).