| 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 |
[16] Antibiotics (Tonsillitis and pharyngitis): Engel MF, Bruns AH, Hulscher ME, Gaillard CA, Sankatsing SU, Teding van Berkhout F, Emmelot-Vonk MH, Kuck EM, Steeghs MH, den Breeijen JH, Stellato RK, Hoepelman AI, Oosterheert JJ. A tailored implementation strategy to reduce the duration of intravenous antibiotic treatment in community-acquired pneumonia: a controlled before-and-after study. Eur J Clin Microbiol Infect Dis. 2014 Nov;33(11):1897-908. https://www.ncbi.nlm.nih.gov/pubmed/24859925