MUSM Libraries: Evaluating a THERAPY article

Appraise |  Estimating the size of treatment effect |  Finding articles


What did they do? (Methods)

1. Were patients randomized?

2. Was randomization concealed?

3. Were patients analyzed in the groups to which they were randomized?

4. Were patients in the treatment and control groups similar with respect to known prognostic factors?

5. Were 5 important groups (patients, caregivers, collectors of outcome data, adjudicators of outcome, data analysts) aware of group allocation?

6. Aside from the experimental intervention, were the groups treated equally?

7. Was follow-up complete?

What was the answer? (Results)

1. How large was the treatment effect?

2. How precise was the estimate of the treatment effect?

What did they say about the answer? (Conclusion)

1. Do the results of the study support the author/s conclusions?

2. Does the conclusion reflect the discussion?

3. Are there study limitations, and do these impact the conclusions?

4. Are potential discrepancies mentioned?

What do I do with this information?

1. Were the study patients similar to my patients?

2. Were all patient important outcomes considered?

3. Are the likely benefits worth the potential harms and costs?

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Estimating the size of the treatment effect

Treated (Y) a b
Control (X) c d

Risk of Outcome: Y = a/(a+b)
Risk of Outcome: X = c/(c+d)

Experimental group size:
Control group size:
Events in experimental group:
Events in control group:


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Finding articles about therapy



From: Guyatt, G. Users' Guides to the Medical Literature: Essentials of Evidence-based Clinical Practice. AMA Press, 2002 and Straus. Evidence-Based Medicine. How to Practice and Teach EBM. Churchill-Livingstone, 3rd edition, 2005 (pocket cards).

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