Registered Nurses' Association of Ontario

Levels of Evidence


Evidence obtained from at least one randomized controlled trial or meta-analysis of randomized controlled trials.


Evidence obtained from well designed clinical studies but no randomized controlled trials.


Evidence obtained from expert committee reports or opinion and/or clinical experience or respected authorities. Indicates absence of directly applicable studies of good quality.

Clinical Management
Assessment and Management of Venous Leg Ulcers
Practice Recommendations