Table 1. Classification of evaluation criteria for evidence quality.

Level	Description
Level I	Evidence from meta-analyses of multiple RCTs or evidence from multiple RCTs.
Level II	Evidence from at least one RCT or evidence from multiple well-designed controlled studies without randomization.
Level III	Evidence obtained from at least one other type of well-designed quasi-experimental study, or evidence obtained from well-designed, non-experimental descriptive studies, such as comparative studies, correlation studies, or case studies.
Level IV	Expert committee reports or opinions and/or clinical experiences of respected authorities.

RCT, randomized controlled trial.