Comment: Stabilizing the Doubly-Robust Estimators of the Average Treatment Effect under Positivity Violations

Doubly-robust estimators within the one-step and TMLE frameworks could exhibit finite-sample bias and excess variability under positivity violations. We comment on how the application of a stabilization factor may improve the efficiency property of one-step estimator and TMLE, and the comparisons with their collaborative counterparts using the adaptive propensity scores.