Covariates-dependent confidence intervals for the difference or ratio of two median survival times

Yuh Ing Chen, Yu Mei Chang

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


In this paper, we are concerned with the estimation of the discrepancy between two treatments when right-censored survival data are accompanied with covariates. Conditional confidence intervals given the available covariates are constructed for the difference between or ratio of two median survival times under the unstratified and stratified Cox proportional hazards models, respectively. The proposed confidence intervals provide the information about the difference in survivorship for patients with common covariates but in different treatments. The results of a simulation study investigation of the coverage probability and expected length of the confidence intervals suggest the one designed for the stratified Cox model when data fit reasonably with the model. When the stratified Cox model is not feasible, however, the one designed for the unstratified Cox model is recommended. The use of the confidence intervals is finally illustrated with a HIV+ data set.

Original languageEnglish
Pages (from-to)2203-2213
Number of pages11
JournalStatistics in Medicine
Issue number10
StatePublished - 10 May 2007


  • Confidence interval
  • Median survival time
  • Right-censored data
  • Stratified Cox model


Dive into the research topics of 'Covariates-dependent confidence intervals for the difference or ratio of two median survival times'. Together they form a unique fingerprint.

Cite this