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Covariate Adjustment Strategy Increases Power in the Randomized Controlled Trial With Discrete-Time Survival Endpoints

Author

Listed:
  • Maryam Safarkhani

    (Utrecht University)

  • Mirjam Moerbeek

    (Utrecht University)

Abstract

In a randomized controlled trial, a decision needs to be made about the total number of subjects for adequate statistical power. One way to increase the power of a trial is by including a predictive covariate in the model. In this article, the effects of various covariate adjustment strategies on increasing the power is studied for discrete-time survival endpoints; the circumstances are examined under which the covariate adjustment results in a sufficient increase in power. Using a predictive covariate may increase the costs for each subject, so it is useful to quantify when using a covariate is a cost-efficient strategy. The results reveal that using a covariate is highly recommended if the costs for measuring the covariate are relatively small and the correlation with the outcome sufficiently high.

Suggested Citation

  • Maryam Safarkhani & Mirjam Moerbeek, 2013. "Covariate Adjustment Strategy Increases Power in the Randomized Controlled Trial With Discrete-Time Survival Endpoints," Journal of Educational and Behavioral Statistics, , vol. 38(4), pages 355-380, August.
  • Handle: RePEc:sae:jedbes:v:38:y:2013:i:4:p:355-380
    DOI: 10.3102/1076998612461832
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    Cited by:

    1. Safarkhani, Maryam & Moerbeek, Mirjam, 2014. "The influence of a covariate on optimal designs in longitudinal studies with discrete-time survival endpoints," Computational Statistics & Data Analysis, Elsevier, vol. 75(C), pages 217-226.

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