Balancing events, not patients, maximizes power of the logrank test: and other insights on unequal randomization in survival trials

Fuente: arXiv
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Main Authors: Yung, Godwin, Rufibach, Kaspar, Wolbers, Marcel, Lin, Ray, Liu, Yi
Format: Preprint
Published: 2024
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author Yung, Godwin
Rufibach, Kaspar
Wolbers, Marcel
Lin, Ray
Liu, Yi
author_facet Yung, Godwin
Rufibach, Kaspar
Wolbers, Marcel
Lin, Ray
Liu, Yi
contents We revisit the question of what randomization ratio (RR) maximizes power of the logrank test in event-driven survival trials under proportional hazards (PH). By comparing three approximations of the logrank test (Schoenfeld, Freedman, Rubinstein) to empirical simulations, we find that the RR that maximizes power is the RR that balances number of events across treatment arms at the end of the trial. This contradicts the common misconception implied by Schoenfeld's approximation that 1:1 randomization maximizes power. Besides power, we consider other factors that might influence the choice of RR (accrual, trial duration, sample size, etc.). We perform simulations to better understand how unequal randomization might impact these factors in practice. Altogether, we derive 6 insights to guide statisticians in the design of survival trials considering unequal randomization.
format Preprint
id arxiv_https___arxiv_org_abs_2407_03420
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Balancing events, not patients, maximizes power of the logrank test: and other insights on unequal randomization in survival trials
Yung, Godwin
Rufibach, Kaspar
Wolbers, Marcel
Lin, Ray
Liu, Yi
Methodology
Applications
We revisit the question of what randomization ratio (RR) maximizes power of the logrank test in event-driven survival trials under proportional hazards (PH). By comparing three approximations of the logrank test (Schoenfeld, Freedman, Rubinstein) to empirical simulations, we find that the RR that maximizes power is the RR that balances number of events across treatment arms at the end of the trial. This contradicts the common misconception implied by Schoenfeld's approximation that 1:1 randomization maximizes power. Besides power, we consider other factors that might influence the choice of RR (accrual, trial duration, sample size, etc.). We perform simulations to better understand how unequal randomization might impact these factors in practice. Altogether, we derive 6 insights to guide statisticians in the design of survival trials considering unequal randomization.
title Balancing events, not patients, maximizes power of the logrank test: and other insights on unequal randomization in survival trials
topic Methodology
Applications
url https://arxiv.org/abs/2407.03420