Research » Glossary of Terms » Levels of Evidence
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The NHMRC levels of evidence relevant to the validation of medical research.
Level l from a systematic review of all relevant randomised controlled trials – meta-analysis.
Level ll from at least one properly designed randomised controlled clinical trial.
Level llla from well-designed pseudorandomised controlled trials (alternate allocation or some other method).
Level lllb from comparative studies (including systematic reviews of such studies) with concurrent controls and allocation not randomised, cohort studies, case-control studies, or interrupted time series with a parallel control group.
Level lllc from comparative studies with historical control, two or more single-arm studies or interrupted time series without a parallel control group.
Level IV opinions of respected authorities based on clinical experience, descriptive studies or reports of expert committees.
Level Vll represents minimal evidence that represents testimonials.