Hutson Alan D
Department of Biostatistics, University at Buffalo, USA.
Stat Methods Med Res. 2018 Feb;27(2):384-397. doi: 10.1177/0962280216630342. Epub 2016 Mar 16.
In this note, we develop a new and novel semi-parametric estimator of the survival curve that is comparable to the product-limit estimator under very relaxed assumptions. The estimator is based on a beta parametrization that warps the empirical distribution of the observed censored and uncensored data. The parameters are obtained using a pseudo-maximum likelihood approach adjusting the survival curve accounting for the censored observations. In the univariate setting, the new estimator tends to better extend the range of the survival estimation given a high degree of censoring. However, the key feature of this paper is that we develop a new two-group semi-parametric exact permutation test for comparing survival curves that is generally superior to the classic log-rank and Wilcoxon tests and provides the best global power across a variety of alternatives. The new test is readily extended to the k group setting.
在本笔记中，我们开发了一种全新的半参数生存曲线估计器，在非常宽松的假设下，它可与乘积限估计器相媲美。该估计器基于贝塔参数化，这种参数化扭曲了观察到的删失和未删失数据的经验分布。参数通过伪最大似然法获得，该方法在考虑删失观测值的情况下调整生存曲线。在单变量设置中，给定高度删失的情况下，新估计器往往能更好地扩展生存估计的范围。然而，本文的关键特性在于，我们开发了一种新的两组半参数精确置换检验来比较生存曲线，该检验通常优于经典的对数秩检验和威尔科克森检验，并且在各种备择假设下都具有最佳的全局功效。新检验很容易扩展到k组设置。
