Propensity score matching is commonly used to draw causal inference from observational survival data. However, its asymptotic properties have yet to be established, and variance estimation is still open to debate. We derive the statistical properties of the propensity score matching estimator of the marginal causal hazard ratio based on matching with replacement and a fixed number of matches. We also propose a double-resampling technique for variance estimation that takes into account the uncertainty due to propensity score estimation prior to matching.

翻译：倾向性评分匹配常用于从观察性生存数据中推断因果效应，但其渐近性质尚未明确建立，并且方差估计仍存争议。本文推导了基于有放回匹配和固定匹配数量的边际因果风险比的倾向性评分匹配估计量的统计性质。同时，我们提出了一种双重重采样技术用于方差估计，该技术考虑了匹配前倾向性评分估计所引入的不确定性。