Absolute Risk Difference Calculator
Estimate an independent-group risk difference with a Newcombe hybrid Wilson confidence interval.
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Estimate an absolute risk difference with an approximate 95% Newcombe hybrid-score interval. All default values are fictional.
Calculation results
Group 1 risk: 0.2
Group 2 risk: 0.1
Risk difference: 0.1
95% lower limit: 0.000149025
95% upper limit: 0.199474
Assumptions and limits
Difference = p1−p2. Uses separate uncorrected Wilson intervals and Newcombe method 10: lower = difference−sqrt((p1−L1)²+(U2−p2)²); upper = difference+sqrt((U1−p1)²+(p2−L2)²). Independent binomial groups only; no continuity correction. Zero/all-event groups are allowed. Not for matched, clustered, adjusted, case-control-sampled or time-to-event risks. Values are proportions; multiply by100 for percentage points. Counts are integers, each total 1–100 million.
Statsmodels: independent-proportion intervals · Read the practical guide · Download blank worksheet (TXT)