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arXiv 2004.05316cs.LGstat.ML
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Ivy:因果推理的工具变量综合

Ivy: Instrumental Variable Synthesis for Causal Inference

Stanford University(斯坦福大学)

Zhaobin Kuang, Frederic Sala, Nimit Sohoni, Sen Wu, Aldo Córdova-Palomera, Jared Dunnmon, James Priest, Christopher Ré

摘要:

从观测数据中估计变量x对y的因果效应的一种流行方法是使用工具变量(IV):第三个变量z,它只通过x影响y。z与x的关联越强,估计值就越可靠,但这样强的IV很难找到。相反,从业者将更常见的IV候选者-不一定是强有力的,甚至是有效的IV-结合到一个单一的“摘要”中,插入因果效应估计器中代替IV。在遗传流行病学中,这种方法被称为等位基因评分。等位基因分数需要强有力的假设-独立性和有效性的所有IV候选人-为所得的估计是可靠的。为了放松这些假设,我们提出了常春藤,一种新的方法来结合IV候选人,可以处理相关的和无效的IV候选人在一个强大的方式。从理论上讲,我们的特点是这种鲁棒性,其限制,其影响所产生的因果估计。从经验上讲,Ivy可以正确识别已知关系的方向性,并且在三个没有因果关系的真实世界数据集上对错误发现具有鲁棒性(中位效应大小<= 0.025),而等位基因得分返回更有偏见的估计(中位效应大小>= 0.118)。

英文摘要:

A popular way to estimate the causal effect of a variable x on y from observational data is to use an instrumental variable (IV): a third variable z that affects y only through x. The more strongly z is associated with x, the more reliable the estimate is, but such strong IVs are difficult to find. Instead, practitioners combine more commonly available IV candidates---which are not necessarily strong, or even valid, IVs---into a single "summary" that is plugged into causal effect estimators in place of an IV. In genetic epidemiology, such approaches are known as allele scores. Allele scores require strong assumptions---independence and validity of all IV candidates---for the resulting estimate to be reliable. To relax these assumptions, we propose Ivy, a new method to combine IV candidates that can handle correlated and invalid IV candidates in a robust manner. Theoretically, we characterize this robustness, its limits, and its impact on the resulting causal estimates. Empirically, Ivy can correctly identify the directionality of known relationships and is robust against false discovery (median effect size <= 0.025) on three real-world datasets with no causal effects, while allele scores return more biased estimates (median effect size >= 0.118).

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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