arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1708.08522stat.MEcs.SImath.STstat.APstat.TH
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网络干扰下的因果推断:一个社交网络实验框架

Causal Inference Under Network Interference: A Framework for Experiments on Social Networks

Edward K. Kao

摘要:

没有人是一座孤岛,因为在我们的社会中,每个人每天都在相互影响。当社会影响发生在一个相互联系的个体群体的实验中时,对一个单元的处理可能会影响其他单元的结果,这种现象被称为干扰。本论文发展了一个因果框架和推理方法的实验干扰发生在网络的影响(即网络干扰)。在这个框架中,网络潜在结果作为关键量和灵活的构建块的因果被估量,代表了各种主要的,同行的,和总的处理效应。这些因果被估量是通过缺失结果的原则贝叶斯插补来估计的。导致简化插补的无混淆假设理论强调了在潜在结局模型中纳入相关网络协变量的重要性。此外,试验设计可使治疗暴露组间的协变量和大小平衡,从而进一步改善因果估计,尤其是通过减少潜在的结局模型错误指定。真实的潜在结果模型在现实世界的实验中通常是未知的,因此最佳实践是通过平衡设计和基于模型的插补来考虑干扰和混淆网络协变量。一个完整的析因模拟实验制定证明这一原则,通过比较不同的随机化方案在设计阶段和估计在分析阶段的性能,根据不同的网络拓扑结构和真正的潜在结果模型。总的来说,这篇论文断言,干扰不只是一个讨厌的分析,而是一个机会,量化和利用同行的影响,在现实世界的实验。

英文摘要:

No man is an island, as individuals interact and influence one another daily in our society. When social influence takes place in experiments on a population of interconnected individuals, the treatment on a unit may affect the outcomes of other units, a phenomenon known as interference. This thesis develops a causal framework and inference methodology for experiments where interference takes place on a network of influence (i.e. network interference). In this framework, the network potential outcomes serve as the key quantity and flexible building blocks for causal estimands that represent a variety of primary, peer, and total treatment effects. These causal estimands are estimated via principled Bayesian imputation of missing outcomes. The theory on the unconfoundedness assumptions leading to simplified imputation highlights the importance of including relevant network covariates in the potential outcome model. Additionally, experimental designs that result in balanced covariates and sizes across treatment exposure groups further improve the causal estimate, especially by mitigating potential outcome model mis-specification. The true potential outcome model is not typically known in real-world experiments, so the best practice is to account for interference and confounding network covariates through both balanced designs and model-based imputation. A full factorial simulated experiment is formulated to demonstrate this principle by comparing performance across different randomization schemes during the design phase and estimators during the analysis phase, under varying network topology and true potential outcome models. Overall, this thesis asserts that interference is not just a nuisance for analysis but rather an opportunity for quantifying and leveraging peer effects in real-world experiments.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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