Level of Evidence | Criteria |
---|---|
Level 1 | Randomized control trials without important limitations |
Level 2 | Randomized control trials with important limitations |
Observational studies (non-randomized clinical trials or cohort studies) with overwhelming evidence | |
Level 3 | Other observational studies (prospective cohort studies, case-control studies, case series) |
Level 4 | Inadequate or no data in population of interest |
Anecdotal evidence or clinical experience |