Part 3.
Appraise: Critically and efficiently appraise the information sources.

How can I decide if a particular study is good enough to apply?

(Estimated time: 0.5 hours)

Introduction
Unless you have found a pre-appraised article (such as a synopsis from an evidence-based journal or a summary statement in Health-Evidence.ca), you will have to assess the methods of the study you have found. In this “critical appraisal” you will judge the quality of the methods, and try to answer the question:

Was this study done well enough that I can be confident in the findings?

Key quality criteria exist for all types of studies in the 6S Pyramid -- systems, summaries, synopses of syntheses, syntheses, synopses of studies, and studies (see Part 2). It is not the intent of this learning module to detail the critical appraisal process for every kind of research report, but to make you aware of the resources where you can get the tools and explanations about their application.

Subsequent learning modules from NCCMT will detail how to critically appraise a systematic review or primary intervention study (available soon at www.nccmt.ca).

A word of caution! People who are new to critical appraisal sometimes throw out relatively well done studies from consideration, because they are not perfect. There are no perfect studies. As you become more familiar with the process, you will see that some criteria that relate to larger concerns would be considered ‘fatal flaws’ for which you would reject the study; however, some other criteria are not as critical and, even if the study has not fulfilled a particular criterion, you could still consider implementing the intervention.

Most of the available tools (including those below) are built from the key criteria developed by the Evidence-Based Medicine Working Group for the series published in JAMA, and later collected in a book (Guyatt & Rennie, 2002). These particular tools are recommended because they are more self-explanatory than most. Each of these recommended tools includes an explanation of the criterion they are asking you to rate – helpful for neophyte critical appraisers.

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