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Hauptverfasser: Cheng, Zhaoxi, Bell, Lauren, Qian, Tianchen
Format: Preprint
Veröffentlicht: 2023
Schlagworte:
Online-Zugang:https://arxiv.org/abs/2311.16529
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author Cheng, Zhaoxi
Bell, Lauren
Qian, Tianchen
author_facet Cheng, Zhaoxi
Bell, Lauren
Qian, Tianchen
contents Causal excursion effect (CEE) characterizes the effect of an intervention under policies that deviate from the experimental policy. It is widely used to study the effect of time-varying interventions that have the potential to be frequently adaptive, such as those delivered through smartphones. We study the semiparametric efficient estimation of CEE and we derive a semiparametric efficiency bound for CEE with identity or log link functions under working assumptions, in the context of micro-randomized trials. We propose a class of two-stage estimators that achieve the efficiency bound and are robust to misspecified nuisance models. In deriving the asymptotic property of the estimators, we establish a general theory for globally robust Z-estimators with either cross-fitted or non-cross-fitted nuisance parameters. We demonstrate substantial efficiency gain of the proposed estimator compared to existing ones through simulations and a real data application using the Drink Less micro-randomized trial.
format Preprint
id arxiv_https___arxiv_org_abs_2311_16529
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Efficient and Globally Robust Causal Excursion Effect Estimation
Cheng, Zhaoxi
Bell, Lauren
Qian, Tianchen
Methodology
Causal excursion effect (CEE) characterizes the effect of an intervention under policies that deviate from the experimental policy. It is widely used to study the effect of time-varying interventions that have the potential to be frequently adaptive, such as those delivered through smartphones. We study the semiparametric efficient estimation of CEE and we derive a semiparametric efficiency bound for CEE with identity or log link functions under working assumptions, in the context of micro-randomized trials. We propose a class of two-stage estimators that achieve the efficiency bound and are robust to misspecified nuisance models. In deriving the asymptotic property of the estimators, we establish a general theory for globally robust Z-estimators with either cross-fitted or non-cross-fitted nuisance parameters. We demonstrate substantial efficiency gain of the proposed estimator compared to existing ones through simulations and a real data application using the Drink Less micro-randomized trial.
title Efficient and Globally Robust Causal Excursion Effect Estimation
topic Methodology
url https://arxiv.org/abs/2311.16529