1. Step 2: Locating the Evidence

2. Table of Contents Evidence Pyramid –Filtered InformationFiltered Information Systematic Reviews/Meta-AnalysesSystematic ReviewsMeta-Analyses Critically-Appraised Topics (Synthesis) Critically-Appraised Articles (Synopsis) –Unfiltered InformationUnfiltered Information Randomized Controlled Trials Cohort Studies Case-Controlled Studies/ Case Series and Reports Background Info/ Expert Opinion

3. Evidence Pyramid The best evidence is located at the top of the pyramid. Click on one of the sources of evidence to learn more.

4. Filtered Information Appraise and/or synthesize information from previous studies Organize it into a single coherent analysis Provide recommendations for future practice.

5. Systematic Reviews/ Meta-Analyses Systematic reviewsSystematic reviews –Comprehensively synthesize and critically appraise information from various articles that meet specific selection criteria –Provide recommendations based on the best evidence available

6. Systematic Reviews/ Meta-Analyses Meta-analysesMeta-analyses –Are systematic reviews using statistical methods to quantitatively combine and summarize several studies’ results

7. Critically-Appraised Topics (Synthesis) Briefly evaluate and synthesize results from several studies on a particular topic that provide the best available evidence relevant to answering a specific clinical question Less rigorous than systematic reviews/meta-analyses

8. Critically-Appraised Articles (Synopsis) Provide a brief synopsis and appraisal of a single study that provides evidence relevant to answering a specific clinical question Less rigorous than systematic reviews/meta-analyses

9. Unfiltered Information The evidence sources from which the above ones acquire their information (i.e. the primary sources) Useful when filtered information is not available

10. Randomized Controlled Trials Randomly assigns subjects into a treatment group or a control group in order to compare the efficacy of a particular treatment, diagnosis, etc. against the current standard, a placebo, or no intervention at all.

11. Cohort Studies Compare two groups of subjects over time, one having a particular condition or receiving a particular treatment, the other not Often used when a randomized controlled trial would be unreasonable or unethical.

12. Case-Controlled Studies/ Case Series and Reports Retrospective observational studies of a particular diagnosis or exposure Determine commonalities in medical history or other associations amongst the affected Can establish correlations, but cannot prove causation

13. Background Info/ Expert Opinion Based on clinical experience and case studies Varies in level of scientific rigor and usefulness.

14. Try it Yourself: Search Basics & Using PubMedSearch Basics & Using PubMed More Advanced Searches & Using the Cochrane LibraryMore Advanced Searches & Using the Cochrane Library

15. Additional Resources for Systematic Reviews\ Meta-Analyses Online Resources: PubMed Cochrane Library Selected Readings: Systematic Reviews: Synthesis of Best Evidence for Clinical Decisions by Cook, D. J., et al.Systematic Reviews: Synthesis of Best Evidence for Clinical Decisions by Cook, D. J., et al.

16. Links to Other Websites and Hands-On Activities From Duke University Medical Center Library and Health Sciences Library, UNC- Chapel Hill –Types of StudiesTypes of Studies From Yale University School of Medicine –Evidence Pyramid from a Slightly Different PerspectiveEvidence Pyramid from a Slightly Different Perspective

17. Congratulations! You have successfully completed Step 2 – Evidence Pyramid. The End