What question did this study set out to answer?

To develop and evaluate a modified logrank test that groups early survival data to prevent distortion from early non-proportional hazards or delayed treatment effects.

March 30, 1997Statistics in Medicine

A Partially Grouped Logrank Test

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Authors

RSRichard SpostoRadiation Effects Research Foundation DSDonald M. StableinUniversity of Southern California SCShelly Carter-CampbellSevenoaks Hospital

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Implication

Simulation study demonstrates a modified logrank test resists early non-proportional hazard distortions, suggesting improved interim monitoring for lagged treatment effects.

Key Points

To develop and evaluate a modified logrank test that groups early survival data to prevent distortion from early non-proportional hazards or delayed treatment effects.
Constructed a modified test statistic where survival data before a pre-specified grouping time are pooled into an initial contingency table using product-limit survival estimates.
Maintained standard logrank calculation procedures for all event contributions occurring after the grouping threshold.
Evaluated the statistical properties, robustness, and relative efficiency of the test using numerical simulation studies across proportional and non-proportional hazard models.
Eliminated sensitivity to non-proportional hazards differences occurring prior to the pre-selected grouping time point.
Maintained statistical efficiency comparable to the standard logrank test under proportional hazards alternatives.
Provided an effective testing framework for interim monitoring when early treatment differences are clinically unimportant or treatment responses are lagged.

Cite This Study

Sposto et al. (1997) studied this question.

synapsesocial.com/papers/6a1572ba79ff98d0de4ea539 https://doi.org/10.1002/(sici)1097-0258(19970330)16:6<695::aid-sim436>3.0.co;2-c

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Implication

Simulation study demonstrates a modified logrank test resists early non-proportional hazard distortions, suggesting improved interim monitoring for lagged treatment effects.

A Partially Grouped Logrank Test

Discussion

Member takes

Implication

Key Points

Cite This Study

A Partially Grouped Logrank Test

Discussion

Member takes

Implication

Key Points

Cite This Study

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