Skip to main content
It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.

Evidence-Based Medicine: Evidence

Scholarly Literature

Understanding Scholarly Literature 

Evidence is found in scholarly literature, which is categorized according to the author(s) position in relation to the information being presented. 

Primary Literature (a.k.a., Empirical Literature)

Primary sources of information report original research, based on direct observation, use of statistical records, interviews or experimental methods.  

Secondary Literature

Secondary sources of information interpret and analyze primary sources of information.  

Publication Types

Various publication types make-up the medical literature.  It can be helpful to familiarize yourself with the different types of publications you might use in the clinical decision-making process.  The list linked here provides information on the publication types indexed for premier biomedical databases, PubMed and MEDLINE.  

Evidence-Based Medicine Information

Unfiltered and Filtered Information

In evidence-based medicine, literature is grouped by the presence or absence of critical appraisal.  Critical appraisal is the process of assessing and interpreting evidence by systematically considering its validity, results, and relevance.  

The strongest evidence lies in the secondary literature.  However, secondary literature is not available for every clinical situation.  When secondary literature is not available for a topic, primary literature must be identified and critically appraised by the clinician. 

For examples, visit the linked resource and search the doi (character string) or title provided.  

Primary literature is Unfiltered (i.e., NOT critically appraised)

Secondary literature is Filtered (i.e., critically appraised and summarized)

Journal Article reporting on RCT

Example: PubMed > 10.1056/NEJMoa1911793

Systematic Review

Example: Cochrane Library > 10.1002/14651858.CD011033.pub4

Review Article

Example: PubMed > 10.1016/j.amjmed.2019.03.036


Example: PubMed > 10.1539/joh.17-0121-ra 

Case Report

Example: PubMed > 10.1016/j.explore.2017.01.002

Critically Appraised Topic

Example: UpToDate > Acute exacerbations of asthma in adults: Home and office management

Clinical Guidelines

Example: TRIP > 0.1016/j.jacc.2016.03.513


Newton Gresham Library | (936) 294-1614 | (866) NGL-INFO | Ask a Question | Share a Suggestion

Sam Houston State University | Huntsville, Texas 77341 | (936) 294-1111 | (866) BEARKAT
© Copyright Sam Houston State University | All rights reserved. | A Member of The Texas State University System