We explore how observational and interventional causal discovery methods can be combined. A state-of-the-art observational causal discovery algorithm for time series capable of handling latent confounders and contemporaneous effects, called LPCMCI, is extended to profit from casual constraints found through randomized control trials. Numerical results show that, given perfect interventional constraints, the reconstructed structural causal models (SCMs) of the extended LPCMCI allow 84.6% of the time for the optimal prediction of the target variable. The implementation of interventional and observational causal discovery is modular, allowing causal constraints from other sources. The second part of this thesis investigates the question of regret minimizing control by simultaneously learning a causal model and planning actions through the causal model. The idea is that an agent to optimize a measured variable first learns the system's mechanics through observational causal discovery. The agent then intervenes on the most promising variable with randomized values allowing for the exploitation and generation of new interventional data. The agent then uses the interventional data to enhance the causal model further, allowing improved actions the next time. The extended LPCMCI can be favorable compared to the original LPCMCI algorithm. The numerical results show that detecting and using interventional constraints leads to reconstructed SCMs that allow 60.9% of the time for the optimal prediction of the target variable in contrast to the baseline of 53.6% when using the original LPCMCI algorithm. Furthermore, the induced average regret decreases from 1.2 when using the original LPCMCI algorithm to 1.0 when using the extended LPCMCI algorithm with interventional discovery.
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重建我们观察到的现象背后的因果关系是科学所有领域的基本挑战。在复杂的系统中,通过实验发现因果关系通常是不可行的,不道德的或昂贵的。但是,计算能力的增加使我们能够处理现代科学生成的不断增长的数据,从而从观察数据中引起对因果发现问题的新兴兴趣。这项工作评估了LPCMCI算法,该算法旨在找到与多维,高度相关的时间序列兼容的生成器,而某些变量则未观察到。我们发现LPCMCI的性能要比模仿什么都不了解的随机算法要好得多,但距离最佳检测仍然很远。此外,LPCMCI在自动依赖性,然后是同时的依赖性方面表现最佳,并且在滞后依赖性方面最挣扎。该项目的源代码可在线获得。
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In this review, we discuss approaches for learning causal structure from data, also called causal discovery. In particular, we focus on approaches for learning directed acyclic graphs (DAGs) and various generalizations which allow for some variables to be unobserved in the available data. We devote special attention to two fundamental combinatorial aspects of causal structure learning. First, we discuss the structure of the search space over causal graphs. Second, we discuss the structure of equivalence classes over causal graphs, i.e., sets of graphs which represent what can be learned from observational data alone, and how these equivalence classes can be refined by adding interventional data.
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考虑基于AI和ML的决策对这些新兴技术的安全和可接受的使用的决策的社会和道德后果至关重要。公平,特别是保证ML决定不会导致对个人或少数群体的歧视。使用因果关系,可以更好地实现和衡量可靠的公平/歧视,从而更好地实现了敏感属性(例如性别,种族,宗教等)之间的因果关系,仅仅是仅仅是关联,例如性别,种族,宗教等(例如,雇用工作,贷款授予等) )。然而,对因果关系解决公平性的最大障碍是因果模型的不可用(通常表示为因果图)。文献中现有的因果关系方法并不能解决此问题,并假设可获得因果模型。在本文中,我们没有做出这样的假设,并且我们回顾了从可观察数据中发现因果关系的主要算法。这项研究的重点是因果发现及其对公平性的影响。特别是,我们展示了不同的因果发现方法如何导致不同的因果模型,最重要的是,即使因果模型之间的轻微差异如何对公平/歧视结论产生重大影响。通过使用合成和标准公平基准数据集的经验分析来巩固这些结果。这项研究的主要目标是强调因果关系使用因果关系适当解决公平性的因果发现步骤的重要性。
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因果关系是理解世界的科学努力的基本组成部分。不幸的是,在心理学和社会科学中,因果关系仍然是禁忌。由于越来越多的建议采用因果方法进行研究的重要性,我们重新制定了心理学研究方法的典型方法,以使不可避免的因果理论与其余的研究渠道协调。我们提出了一个新的过程,该过程始于从因果发现和机器学习的融合中纳入技术的发展,验证和透明的理论形式规范。然后,我们提出将完全指定的理论模型的复杂性降低到与给定目标假设相关的基本子模型中的方法。从这里,我们确定利息量是否可以从数据中估算出来,如果是的,则建议使用半参数机器学习方法来估计因果关系。总体目标是介绍新的研究管道,该管道可以(a)促进与测试因果理论的愿望兼容的科学询问(b)鼓励我们的理论透明代表作为明确的数学对象,(c)将我们的统计模型绑定到我们的统计模型中该理论的特定属性,因此减少了理论到模型间隙通常引起的规范不足问题,以及(d)产生因果关系和可重复性的结果和估计。通过具有现实世界数据的教学示例来证明该过程,我们以摘要和讨论来结论。
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数据科学任务可以被视为了解数据的感觉或测试关于它的假设。从数据推断的结论可以极大地指导我们做出信息做出决定。大数据使我们能够与机器学习结合执行无数的预测任务,例如鉴定患有某种疾病的高风险患者并采取可预防措施。然而,医疗保健从业者不仅仅是仅仅预测的内容 - 它们也对输入特征和临床结果之间的原因关系感兴趣。了解这些关系将有助于医生治疗患者并有效降低风险。通常通过随机对照试验鉴定因果关系。当科学家和研究人员转向观察研究并试图吸引推论时,这种试验通常是不可行的。然而,观察性研究也可能受到选择和/或混淆偏差的影响,这可能导致错误的因果结论。在本章中,我们将尝试突出传统机器学习和统计方法中可能出现的一些缺点,以分析观察数据,特别是在医疗保健数据分析域中。我们将讨论因果化推理和方法,以发现医疗领域的观测研究原因。此外,我们将展示因果推断在解决某些普通机器学习问题等中的应用,例如缺少数据和模型可运输性。最后,我们将讨论将加强学习与因果关系相结合的可能性,作为反击偏见的一种方式。
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因果表示学习是识别基本因果变量及其从高维观察(例如图像)中的关系的任务。最近的工作表明,可以从观测的时间序列中重建因果变量,假设它们之间没有瞬时因果关系。但是,在实际应用中,我们的测量或帧速率可能比许多因果效应要慢。这有效地产生了“瞬时”效果,并使以前的可识别性结果无效。为了解决这个问题,我们提出了ICITRI,这是一种因果表示学习方法,当具有已知干预目标的完美干预措施时,可以在时间序列中处理瞬时效应。 Icitris从时间观察中识别因果因素,同时使用可区分的因果发现方法来学习其因果图。在三个视频数据集的实验中,Icitris准确地识别了因果因素及其因果图。
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A common assumption in causal inference from observational data is that there is no hidden confounding. Yet it is, in general, impossible to verify the presence of hidden confounding factors from a single dataset. Under the assumption of independent causal mechanisms underlying the data generating process, we demonstrate a way to detect unobserved confounders when having multiple observational datasets coming from different environments. We present a theory for testable conditional independencies that are only absent during hidden confounding and examine cases where we violate its assumptions: degenerate & dependent mechanisms, and faithfulness violations. Additionally, we propose a procedure to test these independencies and study its empirical finite-sample behavior using simulation studies and semi-synthetic data based on a real-world dataset. In most cases, our theory correctly predicts the presence of hidden confounding, particularly when the confounding bias is~large.
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在贝叶斯网络(BNS)中,边缘方向对于因果推理和推理至关重要。然而,马尔可夫等价类考虑因素意味着它并不总是可以建立边缘方向,这就是许多BN结构学习算法不能从纯粹观察数据定向所有边缘的原因。此外,潜在的混乱会导致假阳性边缘。已经提出了相对较少的方法来解决这些问题。在这项工作中,我们介绍了从涉及观察数据集的离散数据和一个或多个介入数据集的离散数据的结构学习的混合MFGS-BS(Meance规则和快速贪婪等价搜索)算法。该算法假设存在潜在变量的因果不足,并产生部分祖先图形(PAG)。结构学习依赖于混合方法和新的贝叶斯评分范式,用于计算添加到学习图表的每个定向边缘的后验概率。基于众所周知的网络的实验结果高达109个变量和10K样本大小表明,MFGS-BS相对于最先进的结构提高了结构学习准确性,并且它是计算效率的。
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This review presents empirical researchers with recent advances in causal inference, and stresses the paradigmatic shifts that must be undertaken in moving from traditional statistical analysis to causal analysis of multivariate data. Special emphasis is placed on the assumptions that underly all causal inferences, the languages used in formulating those assumptions, the conditional nature of all causal and counterfactual claims, and the methods that have been developed for the assessment of such claims. These advances are illustrated using a general theory of causation based on the Structural Causal Model (SCM) described in Pearl (2000a), which subsumes and unifies other approaches to causation, and provides a coherent mathematical foundation for the analysis of causes and counterfactuals. In particular, the paper surveys the development of mathematical tools for inferring (from a combination of data and assumptions) answers to three types of causal queries: (1) queries about the effects of potential interventions, (also called "causal effects" or "policy evaluation") (2) queries about probabilities of counterfactuals, (including assessment of "regret," "attribution" or "causes of effects") and (3) queries about direct and indirect effects (also known as "mediation"). Finally, the paper defines the formal and conceptual relationships between the structural and potential-outcome frameworks and presents tools for a symbiotic analysis that uses the strong features of both.
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因果推断对于跨业务参与,医疗和政策制定等领域的数据驱动决策至关重要。然而,关于因果发现的研究已经与推理方法分开发展,从而阻止了两个领域方法的直接组合。在这项工作中,我们开发了深层端到端因果推理(DECI),这是一种基于流动的非线性添加噪声模型,该模型具有观察数据,并且可以执行因果发现和推理,包括有条件的平均治疗效果(CATE) )估计。我们提供了理论上的保证,即DECI可以根据标准因果发现假设恢复地面真实因果图。受应用影响的激励,我们将该模型扩展到具有缺失值的异质,混合型数据,从而允许连续和离散的治疗决策。我们的结果表明,与因果发现的相关基线相比,DECI的竞争性能和(c)在合成数据集和因果机器学习基准测试基准的一千多个实验中,跨数据类型和缺失水平进行了估计。
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因果匪是经典匪徒问题的变体,在该问题中,代理必须在顺序决策过程中识别最佳动作,其中动作的奖励分布显示由因果模型控制的非平凡依赖性结构。到目前为止,文献中针对此问题提出的方法取决于完整因果图的精确知识。我们制定了不再依赖先前因果知识的新因果匪徒。相反,他们利用基于分离集的估计量,我们可以使用简单的条件独立性测试或因果发现方法找到。我们证明,给定一个真正的分离集,用于离散的I.I.D.数据,该估计量是公正的,并且具有差异,该方差受样本平均值的上限。我们分别基于Thompson采样和UCB开发算法,分别用于离散和高斯模型,并显示了模拟数据以及来自现实世界中蛋白质信号数据的强盗图上的性能提高。
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在科学研究和现实世界应用的许多领域中,非实验数据的因果效应的无偏估计对于理解数据的基础机制以及对有效响应或干预措施的决策至关重要。从不同角度对这个具有挑战性的问题进行了大量研究。对于数据中的因果效应估计,始终做出诸如马尔可夫财产,忠诚和因果关系之类的假设。在假设下,仍然需要一组协变量或基本因果图之类的全部知识。一个实用的挑战是,在许多应用程序中,没有这样的全部知识或只有某些部分知识。近年来,研究已经出现了基于图形因果模型的搜索策略,以从数据中发现有用的知识,以进行因果效应估计,并具有一些温和的假设,并在应对实际挑战方面表现出了诺言。在这项调查中,我们回顾了方法,并关注数据驱动方法所面临的挑战。我们讨论数据驱动方法的假设,优势和局限性。我们希望这篇综述将激励更多的研究人员根据图形因果建模设计更好的数据驱动方法,以解决因果效应估计的具有挑战性的问题。
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We present a new algorithm for Bayesian network structure learning, called Max-Min Hill-Climbing (MMHC). The algorithm combines ideas from local learning, constraint-based, and search-and-score techniques in a principled and effective way. It first reconstructs the skeleton of a Bayesian network and then performs a Bayesian-scoring greedy hill-climbing search to orient the edges. In our extensive empirical evaluation MMHC outperforms on average and in terms of various metrics several prototypical and state-of-the-art algorithms, namely the PC, Sparse Candidate, Three Phase Dependency Analysis, Optimal Reinsertion, Greedy Equivalence Search, and Greedy Search. These are the first empirical results simultaneously comparing most of the major Bayesian network algorithms against each other. MMHC offers certain theoretical advantages, specifically over the Sparse Candidate algorithm, corroborated by our experiments. MMHC and detailed results of our study are publicly available at http://www.dsl-lab.org/supplements/mmhc paper/mmhc index.html.
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Learning causal structure from observational data often assumes that we observe independent and identically distributed (i.\,i.\,d) data. The traditional approach aims to find a graphical representation that encodes the same set of conditional independence relationships as those present in the observed distribution. It is known that under i.\,i.\,d assumption, even with infinite data, there is a limit to how fine-grained a causal structure we can identify. To overcome this limitation, recent work has explored using data originating from different, related environments to learn richer causal structure. These approaches implicitly rely on the independent causal mechanisms (ICM) principle, which postulates that the mechanism giving rise to an effect given its causes and the mechanism which generates the causes do not inform or influence each other. Thus, components of the causal model can independently change from environment to environment. Despite its wide application in machine learning and causal inference, there is a lack of statistical formalization of the ICM principle and how it enables identification of richer causal structures from grouped data. Here we present new causal de Finetti theorems which offer a first statistical formalization of ICM principle and show how causal structure identification is possible from exchangeable data. Our work provides theoretical justification for a broad range of techniques leveraging multi-environment data to learn causal structure.
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Linear structural causal models (SCMs)-- in which each observed variable is generated by a subset of the other observed variables as well as a subset of the exogenous sources-- are pervasive in causal inference and casual discovery. However, for the task of causal discovery, existing work almost exclusively focus on the submodel where each observed variable is associated with a distinct source with non-zero variance. This results in the restriction that no observed variable can deterministically depend on other observed variables or latent confounders. In this paper, we extend the results on structure learning by focusing on a subclass of linear SCMs which do not have this property, i.e., models in which observed variables can be causally affected by any subset of the sources, and are allowed to be a deterministic function of other observed variables or latent confounders. This allows for a more realistic modeling of influence or information propagation in systems. We focus on the task of causal discovery form observational data generated from a member of this subclass. We derive a set of necessary and sufficient conditions for unique identifiability of the causal structure. To the best of our knowledge, this is the first work that gives identifiability results for causal discovery under both latent confounding and deterministic relationships. Further, we propose an algorithm for recovering the underlying causal structure when the aforementioned conditions are satisfied. We validate our theoretical results both on synthetic and real datasets.
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本文介绍了一种基于新的条件独立性(CI)的线性和非线性,滞后和同期因因果发现的方法,从而在因果上足够的情况下。基于CI的基于CI的方法,如PC算法以及来自其他框架的常见方法遭受低召回和部分充气的误报,用于强大的自相关,这是时间序列中无处不在的挑战。小说方法PCMCI $ ^ + $,扩展PCMCI [Runge等,2019B],包括发现同期链接。 PCMCI $ ^ + $通过优化调节套件的选择甚至从自相关的益处来提高CI测试的可靠性。该方法在Oracle案例中是单独无关的且一致。广泛的数值实验表明,与其他方法相比,PCMCI $ ^ + $具有更高的邻接检测功率,尤其是同时定向召回,同时更好地控制误报。优化的调节集还会导致比PC算法更短的运行时间。 PCMCI $ ^ + $可以在许多真实世界应用方案中具有相当大的用途,其中通常时间分辨率太粗糙以解决时间延迟,并且存在强大的自相关。
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最近对DataSet Shift的兴趣,已经产生了许多方法,用于查找新的未经,无奈环境中预测的不变分布。然而,这些方法考虑不同类型的班次,并且已经在不同的框架下开发,从理论上难以分析解决方案如何与稳定性和准确性不同。采取因果图形视图,我们使用灵活的图形表示来表达各种类型的数据集班次。我们表明所有不变的分布对应于图形运算符的因果层次结构,该图形运算符禁用负责班次的图表中的边缘。层次结构提供了一个常见的理论基础,以便理解可以实现转移的何时以及如何实现稳定性,并且在稳定的分布可能不同的情况下。我们使用它来建立跨环境最佳性能的条件,并导出找到最佳稳定分布的新算法。使用这种新的视角,我们经验证明了最低限度和平均性能之间的权衡。
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了解因果关系有助于构建干预措施,以实现特定的目标并在干预下实现预测。随着学习因果关系的越来越重要,因果发现任务已经从使用传统方法推断出潜在的因果结构从观察数据到深度学习涉及的模式识别领域。大量数据的快速积累促进了具有出色可扩展性的因果搜索方法的出现。因果发现方法的现有摘要主要集中在基于约束,分数和FCM的传统方法上,缺乏针对基于深度学习的方法的完美分类和阐述,还缺乏一些考虑和探索因果关系的角度来探索因果发现方法范式。因此,我们根据变量范式将可能的因果发现任务分为三种类型,并分别给出三个任务的定义,定义和实例化每个任务的相关数据集以及同时构建的最终因果模型,然后审查不同任务的主要因果发现方法。最后,我们从不同角度提出了一些路线图,以解决因果发现领域的当前研究差距,并指出未来的研究方向。
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药物的因果模型已用于分析机器学习系统的安全性方面。但是,识别代理是非平凡的 - 通常只是由建模者假设而没有太多理由来实现因果模型 - 建模失败可能会导致安全分析中的错误。本文提出了对代理商的第一个正式因果定义 - 大约是代理人是制度,如果他们的行为以不同的方式影响世界,则可以改善其政策。由此,我们得出了第一个用于从经验数据中发现代理的因果发现算法,并提供了用于在因果模型和游戏理论影响图之间转换的算法。我们通过解决不正确的因果模型引起的一些混乱来证明我们的方法。
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