| 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 |
[8] Omeprazole (dose and frequency): Lightdale JR, Gremse D. Gastroensophageal Reflux: Management Guidance for the Pediatrician. American Academy of Pediatrics. Pediatrics. 2013. 131(3): e1684-e1695.