Number Needed to Treat / Absolute Risk Reduction
Number Needed to Treat / Absolute Risk Reduction - a deterministic tool in Sophie Well's Clinical Math & Conversions group.
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What this is
Number Needed to Treat / Absolute Risk Reduction is one of 230 deterministic tools in Sophie Well's Clinical Math & Conversions group. Number Needed to Treat / Absolute Risk Reduction - a deterministic tool in Sophie Well's Clinical Math & Conversions group.
When to use it
Use this tool when you need a quick, citable reference. Every calculation runs entirely in your browser - no inputs leave your device, no account is required, no AI is involved. The site enforces a strict Content Security Policy and ships no analytics or third-party CDN.
References
Laupacis A, Sackett DL, Roberts RS. An assessment of clinically useful measures of the consequences of treatment. N Engl J Med. 1988;318(26):1728-1733. Read the source ↗
Worked example: ARR 5%; NNT 20; relative risk 0.75; RRR 25%.
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