A Proof of Proposition 1 Proof: First, it is straightforward to show that the IPW estimator of the ground truth treatment effect ˆ δ

We proceed to compute the variances of each estimator. The proof also holds for the non-zero mean case trivially. Causal model details for Section 5.2 In Section 5.2, We include a wide range of machine learning-based causal inference methods to evaluate the performance of causal error estimators. Others configs are kept as default. The others are kept as default.