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Medicine - Undergraduate

Explore library resources for Undergraduate Medicine program at McMaster.

iMED Library Orientation

Information Resources & Learning in Medical School

CRAAP Test: criteria for assessing the validity and reliability of information

C   Currency (how old is the information)

R   Reliability (who does the author reference)

A   Authority (does the author have expertise and experience)

A   Accuracy (is the information cited and backed up with evidence)

P   Perspective/bias (does the author provide full and balanced information)


Understanding Evidence-Based Resources

The 6S Hierarchy of Evidence

The 6-S model focuses on appraised literature. Resources at the bottom of the hierachy have not been appraised. Resources from higher on the hierarchy are critically appraised and the evidence is synthesized and often presented in the policy content of a particular country. This model works very well when researching for answers to therapy questions.

A visual representation of the levels of evidence - the 6S pyramid. The bottom of the pyramid is widest with single studies, then synopses of single studeis, then syntheses, then synopses of symtheses, then summaries and finally the top of the pyramid is systems.


[DiCenso, Bayley and Haynes (2009). ACP Journal Club. Editorial: Accessing pre-appraised evidence: Fine-tuning the 5S model into a 6S model. Annals of Internal Medicine, 151(6):JC3-2, JC3-3.]