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.
Keywords: causal survival analysis; double resampling; martingale; propensity score matching; variance estimation.
© 2024 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.