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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

Proportional hazards

The assumption that the ratio of hazards between arms is constant over time. Where the assumption fails, a single hazard ratio summarises a time-varying effect and can mislead.

Document identifier
CEI-GT-068
Series
Defined term
Version
1.0
Published
30 Jul 2026
Last reviewed
30 Jul 2026
Certainty
Not rated

§1Proportional hazards

§1.2Category

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

§1.3Related terms

  • Hazard ratio — The ratio of the instantaneous event rates in two arms, assumed constant over follow-up. A hazard ratio without an absolute risk difference does not convey how much…
Compound Evidence Institute · CEI-GT-068 · https://compoundevidence.com/glossary/proportional-hazards/ · retrieved 30 July 2026
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