Lifetime Data Analysis

, 15:493

First online:

The Gini concentration test for survival data

  • Marco BonettiAffiliated withDepartment of Decision Sciences, Bocconi University Email author 
  • , Chiara GigliaranoAffiliated withDepartment of Economics, Università Politecnica delle Marche
  • , Pietro MuliereAffiliated withDepartment of Decision Sciences, Bocconi University

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We apply the well known Gini index to the measurement of concentration in survival times within groups of patients, and as a way to compare the distribution of survival times across groups of patients in clinical studies. In particular, we propose an estimator of a restricted version of the index from right censored data. We derive the asymptotic distribution of the resulting Gini statistic, and construct an estimator for its asymptotic variance. We use these results to propose a novel test for differences in the heterogeneity of survival distributions, which may suggest the presence of a differential treatment effect for some groups of patients. We focus in particular on traditional and generalized cure rate models, i.e., mixture models with a distribution of the lifetimes of the cured patients that is either degenerate at infinity or has a density. Results from a simulation study suggest that the Gini index is useful in some situations, and that it should be considered together with existing tests (in particular, the Log-rank, Wilcoxon, and Gray–Tsiatis tests). Use of the test is illustrated on the classic data arising from the Eastern Cooperative Oncology Group melanoma clinical trial E1690.


Cure rate model Gini index Linear rank test Melanoma Right censored survival data