Table 1 Level of evidence rating scheme. Based on: Ackley BJ, Swan BA, Ladwig G, & Tucker S. Evidence-based nursing care guidelines: Medical-surgical interventions. St. Louis, MO: Mosby Elsevier. 2008;7
Level of evidence (LOE) | Description |
|---|---|
Level I | Evidence from a systematic review or meta-analysis of all relevant RCTs (randomized controlled trial) or evidence-based clinical practice guidelines based on systematic reviews of RCTs or three or more RCTs of good quality that have similar results. |
Level II | Evidence obtained from at least one well-designed RCT (e.g. large multi-site RCT). |
Level III | Evidence obtained from well-designed controlled trials without randomization (i.e. quasi-experimental). |
Level IV | Evidence from well-designed case-control or cohort studies. |
Level V | Evidence from systematic reviews of descriptive and qualitative studies (meta-synthesis). |
Level VI | Evidence from a single descriptive or qualitative study. |
Level VII | Evidence from the opinion of authorities and/or reports of expert committees. |