arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2006.02482cs.LGcs.AIstat.ML

用因果学习解释黑盒预测算法的行为

Explaining the Behavior of Black-Box Prediction Algorithms with Causal Learning

Sani Analytics;Department of Biostatistics, Columbia University(生物统计学系,哥伦比亚大学);Department of Computer Science, Johns Hopkins University(计算机科学系,约翰霍普金斯大学)

Numair Sani, Daniel Malinsky, Ilya Shpitser

AI总结:

提出学习允许特征间存在未测量混杂的因果图表示方法,用于在仅能查询模型输出的黑盒场景下,区分因果影响预测的可解释特征与仅因混杂相关的特征。

摘要:

针对黑盒预测模型(例如在图像像素数据上训练的深度神经网络)的事后可解释性因果方法变得越来越流行。然而,现有方法存在两个重要缺陷:(i)“解释单元”是相关预测模型的微观层面输入(如图像像素),而不是更有助于理解如何可能改变算法行为的可解释宏观特征;(ii)现有方法假设特征与目标模型预测之间不存在未测量的混杂因素,当解释单元是宏观变量时,这一假设不成立。我们关注的是这样一个重要场景:分析人员无法获取目标预测算法的内部机制,只能针对特定输入查询模型的输出。为了在此场景下提供因果解释,我们提出学习允许特征间存在任意未测量混杂的因果图表示。我们证明所得的图能够区分因果上影响模型预测的可解释特征与仅因混杂而与模型预测相关的特征。我们的方法受因果解释的反事实理论启发,其中好的解释指向干预主义意义上的“差异制造者”因素。

英文摘要:

Causal approaches to post-hoc explainability for black-box prediction models (e.g., deep neural networks trained on image pixel data) have become increasingly popular. However, existing approaches have two important shortcomings: (i) the "explanatory units" are micro-level inputs into the relevant prediction model, e.g., image pixels, rather than interpretable macro-level features that are more useful for understanding how to possibly change the algorithm's behavior, and (ii) existing approaches assume there exists no unmeasured confounding between features and target model predictions, which fails to hold when the explanatory units are macro-level variables. Our focus is on the important setting where the analyst has no access to the inner workings of the target prediction algorithm, rather only the ability to query the output of the model in response to a particular input. To provide causal explanations in such a setting, we propose to learn causal graphical representations that allow for arbitrary unmeasured confounding among features. We demonstrate the resulting graph can differentiate between interpretable features that causally influence model predictions versus those that are merely associated with model predictions due to confounding. Our approach is motivated by a counterfactual theory of causal explanation wherein good explanations point to factors that are "difference-makers" in an interventionist sense.

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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