arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1812.04063stat.ME
收藏

用状态空间模型估计非平稳时间序列中的非均匀处理效应

Estimating heterogeneous treatment effects in nonstationary time series with state-space models

Shu Li, Peter Bühlmann

摘要:

随机试验和观察性研究通常会持续一段时间。处理效应在此期间发生变化,这为治疗反应和长期效果提供了重要见解。许多用于估计处理效应的常规方法限于i.i.d.并且不适于推断处理效应的时间动态。在这些设置中遇到的时间序列是高度信息化的,但往往是非平稳的,由于不断变化的治疗效果。这增加了困难,因为平稳性,时间序列分析中的常见假设,不能合理地假设。另一个挑战是当处理对单元的影响不同时,处理效应的异质性。从非平稳,特别是介入性时间序列中估计异质处理效应的任务是高度相关的,但尚未得到探索。我们提出了因果转移,一种结合回归调整混杂与时间序列建模的方法,以了解治疗的效果以及它如何随着时间的推移而演变。因果转移不假设数据是固定的,可以应用于随机试验和观察性研究,其中治疗是混杂的。因果转移调整可能混杂因素的效应,并将学习效应转移到其他时间序列,从而估计各种形式的处理效应,例如平均处理效应(ATE)或条件平均处理效应(CATE)。通过学习效果的时间动态,因果转移还可以预测未观察到的未来时间点的处理效应,并确定处理的长期后果。

英文摘要:

Randomized trials and observational studies, more often than not, run over a certain period of time. The treatment effect evolves during this period which provides crucial insights into the treatment response and the long-term effects. Many conventional methods for estimating treatment effects are limited to the i.i.d. setting and are not suited for inferring the time dynamics of the treatment effect. The time series encountered in these settings are highly informative but often nonstationary due to the changing effects of treatment. This increases the difficulty, since stationarity, a common assumption in time series analysis, cannot be reasonably assumed. Another challenge is the heterogeneity of the treatment effect when the treatment affects units differently. The task of estimating heterogeneous treatment effects from nonstationary and, in particular, interventional time series is highly relevant but has remained unexplored yet. We propose Causal Transfer, a method which combines regression to adjust for confounding with time series modelling to learn the effect of the treatment and how it evolves over time. Causal Transfer does not assume the data to be stationary and can be applied to randomized trials and observational studies in which treatment is confounded. Causal Transfer adjusts the effect for possible confounders and transfers the learned effect to other time series and, thereby, estimates various forms of treatment effects, such as the average treatment effect (ATE) or the conditional average treatment effect (CATE). By learning the time dynamics of the effect, Causal Transfer can also predict the treatment effect for unobserved future time points and determine the long-term consequences of treatment.

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。

↑