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University Library, University of Illinois at Urbana-Champaign

Evidence-Based Medicine (EBM)

Search for Secondary Literature

Starting with secondary literature can save you time - the searching and appraisal have been done for you...
•Syntheses, Synopses, Summaries
•Saves time (critical appraisal should be explicit)
•Provides concise summary/bottom line
•Indication of level/rigor of evidence
•Look for Evidence Summaries in Clinical Tools
•Look for Systematic Reviews

If secondary literature is inadequate, conflicting, or questions remain, search the primary literature for additional evidence

Searching the Primary Literature

The type of question informs the type of study you want to look for...

Therapy  - RCT | Cohort Study | Case Control Study | Case Series

Diagnosis  - Prospective Study - blind comparison to a gold standard | Cross-Sectional Study

Etiology/Harm - RCT | Cohort Study | Case Control Study |  Case Series

Prognosis - Cohort Study | Case Control Study | Case Series

Prevention - RCT | Cohort Study | Case Control Study | Case Series

Tutorials & Handouts

Levels of Evidence

What kind of evidence?

Database Searching

Develop your search strategy - use PICO concepts to craft search statements.

Create one search statement to represent each concept; be specific; consider synonyms or more specific or broader terms.

Use Boolean operators to combine search statement in various ways.

Apply appropriate limits (dates, language, publication types, etc.)

Save the best citations from each set of results;

Refine the search strategy as you go.

Search is an iterative process. Continue searching as long as you still find new literature.