Table 10

Hierarchy of strength of evidence for therapeutic decisions [slightly modified after [14]]

Level
Description

I
Systematic review of randomized controlled trials (RCTs)
II
Article about an RCT
III
Article about an experimental study without randomization; cohort study; case-control-study
IV
Article about a non-experimental study (cross-sectional study; case series; case report)
V
Narrative review or expert opinion (based on clinical experience) without explicit clinical appraisal (e.g., statements, editorials; expert commentaries to published articles; interviews with experts, brief references to NTI-tss in articles; commercial-like reviews)

Stapelmann and Türp BMC Oral Health 2008 8:22   doi:10.1186/1472-6831-8-22