Zhao G
Henan Institute of Medical Sciences, Henan Medical University, Zhengzhou, China.
Stat Med. 1996 Jan 15;15(1):51-60. doi: 10.1002/(SICI)1097-0258(19960115)15:1<51::AID-SIM141>3.0.CO;2-P.
The homogenetic estimate for the variance of survival rate is proposed based on generalization and reduction between the complement of the empirical distribution function and the Kaplan--Meier or Berkson--Gage estimate. It reduces to the binomial variance estimate when there is no censoring. A Monte Carlo simulation study was carried out under various sample sizes, survival and censoring configurations, number of tied observations, and confidence levels with 2000 replications. It verifies that the commonly employed Greenwood estimate understimates, and the Simon and Lee expression for the Peto estimate strictly overestimates, the variance of survival rate to an extent dependent on the censoring distributions. The conclusions are identical with those of Peto et al. (1977) and Slud et al. (1984). The bias of the homogenetic estimate is less than that of both the Greenwood estimate and the Simon and Lee expression for the Peto estimate. The homogenetic estimate slightly overestimates when there are no ties and becomes unbiased and then slightly underestimates as the number of tied observations increases.
基于经验分布函数的补集与Kaplan-Meier或Berkson-Gage估计之间的推广和简化，提出了生存率方差的同质性估计。在无删失情况下，它简化为二项式方差估计。在不同样本量、生存和删失配置、重复观测数以及置信水平下进行了2000次重复的蒙特卡罗模拟研究。结果验证了常用的Greenwood估计低估了生存率方差，而Peto估计的Simon和Lee表达式则在一定程度上严格高估了生存率方差，其程度取决于删失分布。这些结论与Peto等人（1977年）和Slud等人（1984年）的结论一致。同质性估计的偏差小于Greenwood估计以及Peto估计的Simon和Lee表达式的偏差。当没有重复观测时，同质性估计略有高估，随着重复观测数的增加，它变得无偏，然后略有低估。
