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Centre for Evidence-
Based Medicine

Harm Critical Appraisal Worksheet

Download this worksheet [Word document; 22.5kb]

Are the results of this diagnostic study valid?

Is it clear that the exposure preceded the onset of the outcome?

Are the valid results of this diagnostic study important?

Adverse outcome Totals
Present (case) Absent (control)
Exposed to the treatment


In a randomised trial or cohort study: relative risk = RR = {a/(a+b)}/{c/(c+d)}
In a case-control study: odds ratio (or relative odds) = OR = ad/bc

Should these valid, potentially important results change the treatment of your patient?