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
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.
