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RN-BSN Library Guide

Use this Library Research Guide to help locate evidence-based resources including articles, information on research appraisal, statistics, evidence translation, clinical practice tools, informatics and professional resources.

Levels of Evidence


Level I
Experimental study, randomized controlled trial (RCT)
Systematic review of RCTs, with or without meta-analysis

Level II
Quasi-experimental Study
Systematic review of a combination of RCTs and quasi-experimental, or quasi-experimental studies only, with or without meta-analysis.

Level III
Non-experimental study
Systematic review of a combination of RCTs, quasi-experimental and non-experimental, or non-experimental studies only, with or without meta-analysis.
Qualitative study or systematic review, with or without meta-analysis

Level IV
Opinion of respected authorities and/or nationally recognized expert committees/consensus panels based on scientific evidence.
    Includes:
         - Clinical practice guidelines
         - Consensus panels

Level V
Based on experiential and non-research evidence.
    Includes:
      - Literature reviews
      - Quality improvement, program or financial evaluation
      - Case reports
      - Opinion of nationally recognized expert(s) based on experiential evidence

From Johns Hopkins nursing evidence-based practice : Models and Guidelines This link opens in a new window

Dang, D., & Dearholt, S.L. (2018). Johns Hopkins nursing evidence-based practice : Model & guidelines (3rd ed). Sigma Theta Tau International.

Levels of Evidence


When searching for evidence-based information, one should select the highest level of evidence possible: systematic reviews or meta-analyses. Review the graph to learn more.

pyramid explaining the different levels and quality levels of evidence