Rating System for the Hierarchy of Evidence
Level I: Systematic review or meta-analysis of randomized control trials (RCTs)
Level II: RCTs
Level III: Controlled trials without randomization (also called quasi-experimental studies)
Level IV: Case-control and cohort study
Level V: Systematic review of descriptive or qualitative or mixed methods studies
Level VI: A single descriptive or qualitative study or mixed methods study
Level VII: Experiential and non-research evidence, case reports, or case series
Level VIII: Expert opinion or evidence summaries
Adapted from the following two sources:
Fineout-Overholt, E., Melnyk, B.M., Stillwell, S.B & Williamson, K.M. (2010). Critical appraisal of the evidence: Part I. American Journal of Nursing, 110(7), 47-52.
Dang, D., & Dearholt, S. (2017). Johns Hopkins nursing evidence-based practice: model and guidelines. 3rd ed. Indianapolis, IN: Sigma Theta Tau International.
