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Centre for Evidence-
Based Medicine

Prognosis Critical Appraisal Worksheet

Download this worksheet [Word document; 21kb]

Are the results of this prognosis study valid?






Are the valid results of this prognosis study important?



If you want to calculate a confidence interval around the measure of prognosis

Clinical Measure Standard Error (SE) Typical calculation of CI
Proportion (as in the rate of some prognostic event, etc) where:

the number of patients = n

the proportion of these patients who experience the event = p
sqrt((px(1-p))/n)
where p is proportion and n is number of patients
If p = 24/60 = 0.4 (or 40%) and n=60
sqrt((0.4x(1-0.4))/60)
= 0.063 (or 6.3%)

95% CI is 40% ± 1.96 x 6.3% or 27.6% to 52.4%
:
:
Your calculation:
:
:

Can you apply this valid, important evidence about prognosis in caring for your patient?