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Therapy/Prevention Article
Appraisal Guide

Questions to Ask Yourself

Are the results valid?

1. Was the assignment of patients to treatment randomized?


2. Were all patients who entered the trial properly accounted for and attributed at its conclusion?

blue arrowWas follow-up complete?
blue arrowWere patients analyzed in the groups to which they were randomized ?
blue arrowIntention to treat analysis?

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

blue arrowCo-intervention?
blue arrowContamination?
blue arrowCompliance?


What are the results?

1. How large is the treatment effect?

blue arrowAbsolute risk reduction?
blue arrowRelative risk reduction?

2. Did the study have a sufficiently large sample size?

Vanderbilt- Power and Sample Size Calculator


3. How precise is the estimate of the treatment effect?

blue arrowConfidence intervals?


Will the results help me in patient care?

1. Can the results be applied to my patients?

red ball imagePatients similar for demographics, severity, co-morbidity and other prognostic factors?
red ball imageCompelling reason why they should not be applied?

2. Were all clinically relevant outcomes considered?

red ball imageAre surrogate endpoints valid?


3. Are the benefits worth the harms and costs?

red ball imageNNT for different outcomes?