Repeated confidence intervals for group sequential clinical trials

Christopher Jennison, Bruce W. Turnbull

Research output: Contribution to journalArticlepeer-review


We describe methods for the construction of valid confidence intervals for parameters of interest at repeated times during the course of a clinical trial with two treatments. This approach gives the investigator a way to monitor the trial and allows greater flexibility than methods that have rigid statistical stopping rules. Two situations are considered. In the first, responses are available immediately and normally distributed, the parameter of interest being the difference in means. In the second, observations are survival times and a proportional hazards model is assumed. Here the parameter of interest is the hazard ratio. Group sequential tests can be based on repeated confidence interval methods and these are compared to other multiple testing procedures that have been proposed.

Original languageEnglish
Pages (from-to)33-45
Number of pages13
JournalControlled Clinical Trials
Issue number1
Publication statusPublished - 1 Mar 1984


  • confidence intervals
  • group sequential tests
  • interim analyses
  • proportional hazards

ASJC Scopus subject areas

  • Pharmacology


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