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    基于对抗解耦与分布对齐的个体因果效应估计

    Individual Causal Effect Estimation via Adversarial Disentanglement and Distribution Alignment

    • 摘要: 从观测数据中估计个体因果效应面临的核心挑战在于混杂偏差与反事实结果的不可观测性.为消除混杂偏差,现有方法通常将全部协变量作为混杂因素进行平衡,但错误平衡工具变量和调整变量会引入估计偏差并扩大方差.尽管近期研究通过协变量分解来分离混杂因素,但其样本重加权的平衡方法会引起极端权重,同时忽视了处理组与对照组间的样本失衡问题,导致个体因果效应估计不准确.针对上述局限,本文提出了一种基于对抗学习的个体因果效应估计方法,该方法通过对抗机制优化表示学习与分布平衡.具体来说:i)样本处理:采用SMOTE算法对数据进行预处理,以缓解处理组和对照组样本失衡问题;ii)表示学习:设计两个对抗概率约束模块,通过变量解耦实现混杂因素分离;iii)混杂平衡:通过特征平衡器与对抗判别器动态对齐混杂变量在处理组与对照组中的空间分布,构建对抗平衡网络,避免样本重加权中的极端权重问题.实验结果表明,本算法可以精确地分解混杂因素并提高模型个体因果效应估计的准确性.

       

      Abstract: The core challenge in estimating individual causal effects (ICE) from observational data lies in confounding bias and the unobservability of counterfactual outcomes. To eliminate confounding bias, existing methods typically balance all covariates as potential confounders. However, erroneously balancing instrumental variables and adjustment variables introduces estimation bias and increases variance. Although recent studies address this via covariate decomposition to separate confounders, their sample re-weighting approach for balance can lead to extreme weights while neglecting the sample imbalance between treatment and control groups, resulting in inaccurate ICE estimates. To address these limitations, this paper proposes a Individual Causal Effect Estimation method based on Adversarial Learning, which optimizes representation learning and distribution balancing via an adversarial mechanism. Specifically: (i) Sample Processing: The SMOTE algorithm preprocesses data to mitigate sample imbalance between treatment and control groups; (ii) Representation Learning: Two adversarial probability constraint modules are designed to achieve confounder separation via variable disentanglement; (iii) Confounder Balancing: A feature balancer and an adversarial discriminator dynamically align the spatial distributions of confounders across treatment and control groups, constructing an Adversarial Balancing Network to avoid the extreme weight problem inherent in sample re-weighting. Experimental results demonstrate that our algorithm can precisely decompose confounders and significantly improve the accuracy of ICE estimation.

       

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