Analysis of Restricted Mean Survival Time for Length-biased Data via Empirical Likelihood

Document Type : Original Article

Authors
Department of Statistics, Ordered and Spatial Data Center of Excellence, Ferdowsi University of Mashhad, Mashhad, Iran
10.22034/jirss.2025.2013325.1040
Abstract
The restricted mean survival time (RMST) in the context of length-biased data is an important addition to clinical studies. The RMST is a widely used measurement for evaluating survival over a specific period, and the area under the survival function is a key component of this metric. However, when the data under study are length-biased, traditional parametric and classical methods for examining the RMST are not applicable. Nonparametric and semi-parametric methods are used to address this issue. We utilize the empirical likelihood (EL) method to investigate RMST.
Our proposed EL procedure provides a reliable approach for inferential analysis of RMST in the presence of length-biased data. We have shown that the limiting distribution of the empirical log-likelihood ratio is a chi-square distribution with one degree of freedom. We also demonstrated that the likelihood ratio exhibits weak convergence to a mean-zero Gaussian process, which we used to construct a confidence band.
In our simulation section, we compared the confidence intervals obtained from the normal approximation (NA) and EL methods. We showed that the EL method has a better coverage probability than the NA method. Additionally, we provided a real data application using bank customers' monthly taxes to illustrate further the effectiveness of our proposed method.
Keywords
Subjects

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Volume 23, Issue 2
December 2024
Pages 69-96

  • Receive Date 12 October 2023
  • Revise Date 21 February 2025
  • Accept Date 25 March 2025