| Level I | Good quality evidence |
Systematic review of RCTs with consistent findings High quality individual RCT |
| Level II |
Limited quality patient orientated evidence |
Systematic review of lower quality studies or studies with inconsistent findings Low quality clinical trial Cohort studies Case-control studies |
| Level III | Other |
Consensus guidelines, extrapolations from bench research, usual practice, opinion, disease-oriented evidence (intermediate or physiologic outcomes only), or case series |
[1] Androgens:Wilkins L. Masculinization of female fetus due to use of orally given progestins. JAMA. 1960 Mar 5;172(10):1028–32. https://jamanetwork.com/journals/jama/article-abstract/327726