Hierarchy of evidence

Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [1] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.

Evidence hierarchies reflect the relative authority of various types of biomedical research. Although there is no single, universally-accepted hierarchy of evidence, there is broad agreement on the relative strength of the principal types of research. Randomized controlled trials (RCTs) rank above observational studies, while expert opinion and anecdaotal experience are ranked at the bottom. Some evidence hierarchies place systematic review and meta analysis above RCTs, since these often combine data from multiple RCTs, and possibly from other study types as well. Evidence hierarchies are integral to evidence-based medicine.

The use of evidence hierarchies has been criticized as allowing RCTs too much authority. Not all research questions can be answered through RCTs, either because of practical issues or because of ethical issues. Moreover, even when evidence is available from high-quality RCTs, evidence from other study types may still be relevant.

Ranking:

1. Systematic Reviews and Meta-Analysis

2. Randomized Controlled Trials with definite results

3. Randomized Controlled Trials with no definite results

4. Cohort Studies

5. Case-Control Studies

6. Cross-Sectional Studies

7. Case Reports

8. Expert Opinion

9. Anecdotes

External links

School of Health and Related Research, University of Sheffield, "Hierarchy of evidence". http://www.shef.ac.uk/scharr/ir/units/systrev/hierarchy.htm. Accessed 2008-03-31.

Template:WS