Doubly-robust evaluation of high-dimensional surrogate markers

Abstract

When evaluating the effectiveness of a treatment, policy, or intervention, the desired measure of effectiveness may be expensive to collect, not routinely available, or may take a long time to occur. In these cases, it is sometimes possible to identify a surrogate outcome that can more easily/quickly/cheaply capture the effect of interest. Theory and methods for evaluating the strength of surrogate markers have been well studied in the context of a single surrogate marker measured in the course of a randomized clinical study. However, methods are lacking for quantifying the utility of surrogate markers when the dimension of the surrogate grows and/or when study data are observational. We propose an efficient nonparametric method for evaluating high-dimensional surrogate markers in studies where the treatment need not be randomized. Our approach draws on a connection between quantifying the utility of a surrogate marker and the most fundamental tools of causal inference -- namely, methods for estimating the average treatment effect. We show that recently developed methods for incorporating machine learning methods into the estimation of average treatment effects can be used for evaluating surrogate markers. This allows us to derive limiting asymptotic distributions for key quantities, and we demonstrate their good performance in simulation.

References in corpus (7)

• Nearly unbiased variable selection under minimax concave penalty
• Robust Inference on Average Treatment Effects with Possibly More Covariates than Observations
• Deep Neural Networks for Estimation and Inference
• Adaptive Concentration of Regression Trees, with Application to Random Forests
• Estimating Treatment Effects using Multiple Surrogates: The Role of the Surrogate Score and the Surrogate Index
• A unifying approach for doubly-robust ${\ell }_1$ regularized estimation of causal contrasts
• Improved Estimation of Average Treatment Effects on the Treated: Local Efficiency, Double Robustness, and Beyond