Exact Inference for Adaptive Group Sequential Designs

  • Cyrus MehtaEmail author
  • Lingyun Liu
  • Pranab Ghosh
  • Ping Gao
Conference paper
Part of the Springer Proceedings in Mathematics & Statistics book series (PROMS, volume 218)


In this paper we present a method for estimating the treatment effect in a two-arm adaptive group sequential clinical trial that permits sample size re-estimation, alterations to the number and spacing of the interim looks, and changes to the error spending function based on an unblinded look at the accruing data. The method produces a median unbiased point estimate and a confidence interval having exact coverage of the parameter of interest. The procedure is based on mapping the final test statistic obtained in the modified trial into a corresponding backward image in the original trial. Methods that were developed for classical (non-adaptive) group sequential inference can then be applied to the backward image.


Estimation in adaptive design Exact adaptive confidence intervals Adaptive median unbiased estimates Group sequential estimation 


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Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Cyrus Mehta
    • 1
    • 2
    Email author
  • Lingyun Liu
    • 1
  • Pranab Ghosh
    • 1
  • Ping Gao
    • 3
  1. 1.Cytel CorporationCambridgeUSA
  2. 2.Harvard School of Public HealthBostonUSA
  3. 3.Brightech-InternationalSomersetUSA

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