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arXiv 2008.06461stat.MEstat.ML
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利用机器学习和影响函数估计结构目标函数

Estimating Structural Target Functions using Machine Learning and Influence Functions

Alicia Curth, Ahmed M. Alaa, Mihaela van der Schaar

摘要:

我们的目标是构建一类学习算法,具有实用价值的应用研究人员在生物统计学,流行病学和计量经济学等领域,需要学习不完全观察到的信息是无处不在的。我们提出了一个新的框架,统计机器学习的目标函数所产生的可识别的泛函从统计模型,我们称之为"IF学习",由于其依赖于影响函数(IF)。这个框架是问题和模型不可知的,可以用来估计各种各样的目标参数的兴趣在应用统计学:我们可以考虑任何目标函数的IF的人口平均版本存在于分析形式。在整个过程中,我们特别关注所谓的随机粗化/部分未观测信息的双重鲁棒问题。这包括诸如处理效应估计和在存在缺失结果数据的情况下的推断等问题。在这个框架内,我们提出了两种通用的学习算法,它们基于通过IF去除非参数插件偏差的想法:"IF-学习器",其使用由非中心IF激励的伪结果用于大样本中的回归,并输出没有置信带的整个目标函数,以及"组IF-学习器",其仅输出对函数的近似,但是如果关于粗化机制的足够信息可用,则可以给出置信度估计。我们将两者应用于推断处理效应的模拟研究中。

英文摘要:

We aim to construct a class of learning algorithms that are of practical value to applied researchers in fields such as biostatistics, epidemiology and econometrics, where the need to learn from incompletely observed information is ubiquitous. We propose a new framework for statistical machine learning of target functions arising as identifiable functionals from statistical models, which we call `IF-learning' due to its reliance on influence functions (IFs). This framework is problem- and model-agnostic and can be used to estimate a broad variety of target parameters of interest in applied statistics: we can consider any target function for which an IF of a population-averaged version exists in analytic form. Throughout, we put particular focus on so-called coarsening at random/doubly robust problems with partially unobserved information. This includes problems such as treatment effect estimation and inference in the presence of missing outcome data. Within this framework, we propose two general learning algorithms that build on the idea of nonparametric plug-in bias removal via IFs: the 'IF-learner' which uses pseudo-outcomes motivated by uncentered IFs for regression in large samples and outputs entire target functions without confidence bands, and the 'Group-IF-learner', which outputs only approximations to a function but can give confidence estimates if sufficient information on coarsening mechanisms is available. We apply both in a simulation study on inferring treatment effects.

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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