Table 3.

Level of evidence derived from the Journal of American Academy of Dermatology guidelines

Level	Description
I-A	Evidence from a meta-analysis of randomized controlled trials
I-B	Evidence from at least one randomized controlled trial
II-A	Evidence from at least one controlled study without randomization
II-B	Evidence from at least one other type of experimental study
III	Evidence from nonexperimental descriptive studies (comparative studies, correlation studies, and case-control studies)
IV	Evidence from expert committee reports or opinions or clinical experience of respected authorities, or both