Registered Nurses' Association of Ontario

Levels of Evidence


Evidence obtained from meta-analysis or systematic review of randomized controlled trials

Ib Evidence obtained from at least one randomized controlled trial.
IIa Evidence obtained from at least one well-designed controlled study without randomization.

Evidence obtained from at least one other type of well-designed quasi- experimental study, without  randomization.

III Evidence obtained from well-designed, non-experimental descriptive studies, such as comparative studies, correlation studies and case studies.

Evidence obtained from expert committee reports or opinions and/or clinical experiences of respected authorities



Chronic Disease
Decision Support for Adults Living with Chronic Kidney Disease
Practice Recommendations