Why Is the Double-Robust Estimator for Causal Inference Not Doubly Robust for Variance Estimation?
为何因果推断的双重稳健估计量在方差估计上并非双重稳健
Doubly robust estimators (DRE) are widely used in causal inference because they yield consistent estimators of average causal effect when at least one of the nuisance models, the propensity for treatment (exposure) or the outcome regression, is correct. However, double robustness does not extend to variance estimation; the influence-function (IF)-based variance estimator is consistent only when both nuisance parameters are correct. This raises concerns about applying DRE in…