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Compound Evidence InstituteEvidence synthesis · established 2023Graded assessments of compounds, trials, methods and supply
Document set current to 30 July 2026
Defined term · Statistics and inference

Odds ratio

The ratio of the odds of an event in two arms. Approximates the risk ratio only when the event is uncommon, and departs from it materially for common outcomes.

Document identifier
CEI-GT-071
Series
Defined term
Version
1.0
Published
30 Jul 2026
Last reviewed
30 Jul 2026
Certainty
Not rated

§1Odds ratio

§1.1Also known as

OR

§1.2Category

Statistics and inference — Terms describing how effects are estimated and how uncertainty is expressed.

§1.3Related terms

  • Risk ratio — The ratio of event probabilities in two arms. More directly interpretable than an odds ratio for common outcomes.
Compound Evidence Institute · CEI-GT-071 · https://compoundevidence.com/glossary/odds-ratio/ · retrieved 30 July 2026
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