论文标题

估计纵向二元结果的时变直接和间接因果偏移效应

Estimating Time-Varying Direct and Indirect Causal Excursion Effects with Longitudinal Binary Outcomes

论文作者

Shi, Jieru, Wu, Zhenke, Dempsey, Walter

论文摘要

构建即时自适应干预措施,例如移动应用程序提供的提示以促进和维持行为改变,需要有关随时间变化的调节效果的知识,以告知我们何时以及如何提供干预选项。微型试验(MRT)已成为一种顺序随机设计,以收集必要的数据以进行效果估计。现有文献(Qian等,2020; Boruvka等,2018; Dempsey等,2020)定义了一类普通因果估计,称为“因果偏移效应”,以评估时间变化的适度效应。然而,关于如何解决纵向二进制结果的顺序治疗环境中的群集治疗效果异质性和群内干扰的潜在统计文献有限。在本文中,基于潜在结果的集群概念化,我们为近端和滞后二进制结果定义了更大类别的直接和间接因果偏移效应,并提出了一种解决效果的新推论程序,该程序效果效果异质性和干扰。我们提供了一致性和估算仪的渐近正态性的理论保证。广泛的仿真研究通过经验证实了我们的理论,并表明所提出的程序提供了一致的点估计器和间隔估计值,并具有有效的覆盖范围。最后,我们分析了来自多机构的MRT研究中的数据集,以评估移动提示对二元研究参与结果的随着时间变化的调节作用。

Construction of just-in-time adaptive interventions, such as prompts delivered by mobile apps to promote and maintain behavioral change, requires knowledge about time-varying moderated effects to inform when and how we deliver intervention options. Micro-randomized trials (MRT) have emerged as a sequentially randomized design to gather requisite data for effect estimation. The existing literature (Qian et al., 2020; Boruvka et al., 2018; Dempsey et al., 2020) has defined a general class of causal estimands, referred to as "causal excursion effects", to assess the time-varying moderated effect. However, there is limited statistical literature on how to address potential between-cluster treatment effect heterogeneity and within-cluster interference in a sequential treatment setting for longitudinal binary outcomes. In this paper, based on a cluster conceptualization of the potential outcomes, we define a larger class of direct and indirect causal excursion effects for proximal and lagged binary outcomes, and propose a new inferential procedure that addresses effect heterogeneity and interference. We provide theoretical guarantees of consistency and asymptotic normality of the estimator. Extensive simulation studies confirm our theory empirically and show the proposed procedure provides consistent point estimator and interval estimates with valid coverage. Finally, we analyze a data set from a multi-institution MRT study to assess the time-varying moderated effects of mobile prompts upon binary study engagement outcomes.

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