A Class of Permutation Tests for the Equality of Two Marginal Survival Functions Using Paired Censored Data

Abstract

We studied several test statistics for testing the equality of marginal survival functions of paired censored data. The null distribution of the test statistics was approximated by permutation. These tests do not require explicit modeling or estimation of the within-pair correlation, accommodate both paired data and singletons, and the computation is straightforward with most statistical software. Numerical studies showed that these tests have competitive size and power performance. One test statistic has higher power than previously published test statistics when the two survival functions under comparison cross. We illustrate use of these tests in a propensity score matched dataset.

Keywords:

• Crossing survival functions
• Nonproportional hazard
• Paired censored data
• Paired survival data
• Permutation test
• Propensity score matching

Mathematics Subject Classification:

• Primary 62N03
• Secondary 62G09

Acknowledgments

This publication was made possible by the Case Western Reserve University/Cleveland Clinic CTSA Grant Number UL1 RR024989 from the National Center for Research Resources (NCRR), a component of the National Institutes of Health and NIH roadmap for Medical Research. Its contents are solely the responsibility of the authors and do not necessarily represent the official view of NCRR or NIH. The author thanks Professor Susan Murray of University of Michigan for providing the R code that performs the large sample WKM test proposed in Murray (2001). The author also thanks the Associate Editor and a referee for their constructive comments, which greatly improved this article.