Attributable Risk


The following is a 2 by 2 webulator used to compute Attributable Risk . Enter the data in the cells for the appropriate rows and columns (the green coloured cells), then click on the button labelled Compute to compute the Attributable Risk .

+ve condition (CASES) -ve condition (CONTROLS) Numerator (a/(a+b))
+ve condition (CASES) -ve condition (CONTROLS) Denominator (c/(c+d))
Not Exposed
Column Totals =
Attributable Risk =
(a/ (a+b)) - (c/(c+d))

Standard Error of Attributable Risk
Confidence Interval
95% CI lower limit
95% CI upper limit

Given that the confidence interval does not include 0 we can say that consistent with the test of the null hypothesis, the observed attributable risk estimate is significant at the p<0.05 level; and that exposure can increase the risk of a suspected outcome.

Click here to return to the Webulator Menu Page

For more information, please contact:

Professor William J. Montelpare, Ph.D.,
Margaret and Wallace McCain Chair in Human Development and Health,
Department of Applied Human Sciences, Faculty of Science,
Health Sciences Building, University of Prince Edward Island,
550 Charlottetown, PE, Canada, C1A 4P3
(o) 902 620 5186

Visiting Professor, School of Healthcare, University of Leeds,
Leeds, UK, LS2 9JT
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