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A Guide for Nurses and Nursing Students



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.

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