Lifetime Data Analysis

, Volume 11, Issue 1, pp 117–129 | Cite as

Pair Chart Test for an Early Survival Difference

  • Guosheng Yin
  • Donglin Zeng


The log-rank test is commonly used in comparing survival distributions between treatment and control groups in clinical trials. However, in many studies, the treatment is only effective at the early stage of the trial. Especially when the two survival curves cross, the log-rank test has a low statistical power to show the survival difference. We propose a test statistic for detecting such an early difference between the two treatment arms. The new test has an intuitive geometric interpretation based on a pair chart and is shown to have more power than the log-rank test when the treatment effect only appears in the early phase of the study. This advantage is evaluated for finite sample sizes in simulation studies. Finally, the proposed method is illustrated with a real data example of patients with gastric cancer.


early treatment effect log-rank test pair chart statistic survival comparison 


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Copyright information

© Springer Science+Business Media, Inc. 2005

Authors and Affiliations

  1. 1.Department of Biostatistics, M. D. Anderson Cancer CenterThe University of TexasUSA
  2. 2.Department of BiostatisticsUniversity of North Carolina at Chapel HillChapel HillUSA

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