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Step 2:. Locating the Evidence. Table of Contents. Evidence Pyramid Filtered Information Systematic Reviews / Meta-Analyses Critically-Appraised Topics (Synthesis) Critically-Appraised Articles (Synopsis) Unfiltered Information Randomized Controlled Trials Cohort Studies
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Step 2: Locating the Evidence
Table of Contents • Evidence Pyramid • Filtered Information • Systematic Reviews/Meta-Analyses • Critically-Appraised Topics (Synthesis) • Critically-Appraised Articles (Synopsis) • Unfiltered Information • Randomized Controlled Trials • Cohort Studies • Case-Controlled Studies/ Case Series and Reports • Background Info/ Expert Opinion
Evidence Pyramid • The best evidence is located at the top of the pyramid. • Click on one of the sources of evidence to learn more.
Filtered Information • Appraise and/or synthesize information from previous studies • Organize it into a single coherent analysis • Provide recommendations for future practice.
Systematic Reviews/ Meta-Analyses • Systematic reviews • Comprehensively synthesize and critically appraise information from various articles that meet specific selection criteria • Provide recommendations based on the best evidence available
Systematic Reviews/ Meta-Analyses • Meta-analyses • Are systematic reviews using statistical methods to quantitatively combine and summarize several studies’ results
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
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
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
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.
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.
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
Background Info/ Expert Opinion • Based on clinical experience and case studies • Varies in level of scientific rigor and usefulness.
Try it Yourself: • Search Basics & Using PubMed • More Advanced Searches & Using the Cochrane Library
Additional Resources forSystematic 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.
Links to Other Websitesand Hands-On Activities • From Duke University Medical Center Library and Health Sciences Library, UNC-Chapel Hill • Types of Studies • From Yale University School of Medicine • Evidence Pyramid from a Slightly Different Perspective
Congratulations!You have successfully completed Step 2 – Evidence Pyramid.The End