Augmented outcome-weighted learning for estimating optimal dynamic treatment regimens

By Ying Liu, Yuanjia Wang, Michael R. Kosorok, Ying‐Qi Zhao, Donglin Zeng. 2018

95 citations recorded by the source corpus.

Dynamic treatment regimens (DTRs) are sequential treatment decisions tailored by patient's evolving features and intermediate outcomes at each treatment stage. Patient heterogeneity and the complexity and chronicity of many diseases call for learning optimal DTRs that can best tailor treatment according to each individual's time‐varying characteristics (eg, intermediate response over time). In this paper, we propose a robust and efficient approach referred to as Augmented Outcome‐weighted Learning (AOL) to identify optimal DTRs from sequential multiple assignment randomized trials. We improve previously proposed outcome‐weighted learning to allow for negative weights. Furthermore, to reduce the variability of weights for numeric stability and improve estimation accuracy, in AOL, we propose a robust augmentation to the weights by making use of predicted pseudooutcomes from regression models for Q‐functions. We show that AOL still yields Fisher‐consistent DTRs even if the regression models are misspecified and that an appropriate choice of the augmentation guarantees smaller stochastic errors in value function estimation for AOL than the previous outcome‐weighted learning. Finally, we establish the convergence rates for AOL. The comparative advantage of AOL over existing methods is demonstrated through extensive simulation studies and an application to a sequential multiple assignment randomized trial for major depressive disorder.

Subfields: Economics and Econometrics, Statistics and Probability

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Citations in the corpus

Learning When-to-Treat Policies (2019, methodology): “In observational studies treatment probabilities need to be estimated from data, and it is known that the variant of (6) with estimated weights γ̂ (i)t (π) can perform poorly with even mild estimation error (see, e.g., Y. Liu et al. 2018).”