Specifying and Implementing Nonparametric and Semiparametric Survival Estimators in Two-Stage (Nested) Cohort Studies With Missing Case Data
病例测量缺失的两阶段队列研究：生存估计量的设定与实现
Since 1986, we have been studying a cohort of individuals from a region in China with epidemic rates of gastric cardia cancer and have conducted numerous two-stage studies to assess the association of various exposures with this cancer. Two-stage studies are a commonly used statistical design. Stage one involves observing the outcomes and accessible baseline covariate information on all cohort members, and stage two involves using the stage one observations to select a…