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. 2020 Apr 14;323(14):1401-1402.
doi: 10.1001/jama.2020.1267.

Why Test for Proportional Hazards?

Mats J Stensrud  1   2 , Miguel A Hernán  1   3   4
Affiliations

Why Test for Proportional Hazards?

Mats J Stensrud et al. JAMA. .
No abstract available

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Conflict of interest statement

Conflict of Interest Disclosures: Dr Stensrud reported receiving grants from the Research Council of Norway (NFR239956/F20) and the ASISA Fellowship. Dr Hernán reported receiving a grant from the National Institutes of Health (R37 AI102634).

Figures

Figure.
Figure.. Nonproportional Hazards and Survival Curves in 3 Hypothetical Trials Comparing a Treatment vs a Control
In scenario 1, both the hazards (dotted lines) and the survival curves (solid lines) gradually diverge (ie, the hazard ratio is not constant but is always greater than 1). In scenario 2, both the hazards and the survival curves cross (ie, the hazard ratio goes from greater than 1 to less than 1). In scenario 3, the hazards cross because of depletion of susceptibles in the treatment group, but the survival curves do not cross. The hazards would have been proportional if the dotted lines were straight and horizontal.
See this image and copyright information in PMC

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