🤖 AI Summary
This work addresses the lack of theoretical justification for the widespread use of bootstrap inference with double/debiased machine learning (DML) estimators. It proposes a unified framework that integrates exchangeable weighted resampling, Neyman-orthogonal scores, and cross-fitting, and establishes—under the same conditions required for DML consistency—that the conditional distribution of the bootstrap approximates the sampling distribution of the original estimator in the sense of weak convergence. This result encompasses the classical Efron bootstrap as a special case. By rigorously validating bootstrap-based inference for DML, the paper provides the first formal theoretical foundation for this commonly employed practice, thereby filling a critical gap in the existing literature.
📝 Abstract
Double/debiased machine learning (DML) provides a general framework for inference with high-dimensional or otherwise complex nuisance parameters by combining Neyman-orthogonal scores with cross-fitting, thereby circumventing classical Donsker-type conditions in many modern machine-learning settings. Despite its strong empirical performance, bootstrap inference for DML estimators has received little theoretical justification. This is particularly noteworthy since bootstrap methods are suggested ad used for inference on DML estimators, even though bootstrap procedures can fail for estimators that are root-$n$ consistent and asymptotically normal. This paper fills this gap by establishing bootstrap validity for DML estimators under general exchangeably weighted resampling schemes, with Efron's bootstrap as a special case. Under exactly the same conditions required for the validity of DML itself, we prove that the bootstrap law converges conditionally weakly to the sampling law of the original estimator.