TABLE 2.
Level | Definition |
---|---|
I | Evidence from at least one properly randomized controlled trial |
II | Evidence from at least one well-designed clinical trial without randomization, from cohort or case-controlled analytical studies, (preferably from more than one centre), from multiple time series, or dramatic results in uncontrolled experiments |
III | Evidence from opinions of respected authorities on the basis of clinical experience, descriptive studies, or reports or expert comittees |