在机器学习(ML)算法自动化或提供有关人员的后果决策的环境中,通常会激励个人决策主题以战略性地修改其可观察的属性以获得更有利的预测。结果,对评估规则进行培训的分布可能与其部署中运营的规则不同。尽管这种分配的变化通常可以阻碍准确的预测,但我们的工作确定了由于战略反应而引起的转变相关的独特机会:我们表明我们可以有效地利用战略反应来恢复可观察到的特征与我们希望预测的可观察到的因果关系,即使在没有观察到的混杂变量的情况下。具体而言,我们的工作通过观察到部署模型的序列可以看作是影响代理可观察到的特征但不会直接影响其结果的工具,从而建立了对ML模型的战略响应与仪器变量(IV)回归之间的新颖联系。我们表明,我们的因果恢复方法可用于改善几个重要标准的决策:个人公平,代理结果和预测风险。特别是,我们表明,如果决策主体在修改非毒物属性的能力上有所不同,那么与因果系数偏离的任何决策规则都可能导致(潜在无限)个体级别的不公平性。
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在许多预测性决策方案(例如信用评分和学术测试)中,决策者必须构建一个模型,该模型通过更改其功能来说明代理商“游戏”决策规则的倾向,从而获得更好的决策。尽管战略分类文献以前已经假设代理人的结果并不受其特征的因果影响(因此战略代理人的目标是欺骗决策者),但我们加入了并发的工作,以建模代理人的成果作为其可变化的函数属性。作为我们的主要贡献,我们为学习决策规则提供有效的算法,以在可实现的线性环境中优化三个不同的决策制定目标:准确预测代理的胶结后结果(预测风险最小化),激励代理人改善这些结果(代理结果(代理结果)最大化),并估计真实基础模型的系数(参数估计)。我们的算法避免了Miller等人的硬度结果。 (2020)允许决策者测试一系列决策规则并观察代理人的反应,实际上是通过决策规则执行因果干预措施的。
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基于AI和机器学习的决策系统已在各种现实世界中都使用,包括医疗保健,执法,教育和金融。不再是牵强的,即设想一个未来,自治系统将推动整个业务决策,并且更广泛地支持大规模决策基础设施以解决社会最具挑战性的问题。当人类做出决定时,不公平和歧视的问题普遍存在,并且当使用几乎没有透明度,问责制和公平性的机器做出决定时(或可能会放大)。在本文中,我们介绍了\ textit {Causal公平分析}的框架,目的是填补此差距,即理解,建模,并可能解决决策设置中的公平性问题。我们方法的主要见解是将观察到数据中存在的差异的量化与基本且通常是未观察到的因果机制收集的因果机制的收集,这些机制首先会产生差异,挑战我们称之为因果公平的基本问题分析(FPCFA)。为了解决FPCFA,我们研究了分解差异和公平性的经验度量的问题,将这种变化归因于结构机制和人群的不同单位。我们的努力最终达到了公平地图,这是组织和解释文献中不同标准之间关系的首次系统尝试。最后,我们研究了进行因果公平分析并提出一本公平食谱的最低因果假设,该假设使数据科学家能够评估不同影响和不同治疗的存在。
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解决公平问题对于安全使用机器学习算法来支持对人们的生活产生关键影响的决策,例如雇用工作,儿童虐待,疾病诊断,贷款授予等。过去十年,例如统计奇偶校验和均衡的赔率。然而,最新的公平概念是基于因果关系的,反映了现在广泛接受的想法,即使用因果关系对于适当解决公平问题是必要的。本文研究了基于因果关系的公平概念的详尽清单,并研究了其在现实情况下的适用性。由于大多数基于因果关系的公平概念都是根据不可观察的数量(例如干预措施和反事实)来定义的,因此它们在实践中的部署需要使用观察数据来计算或估计这些数量。本文提供了有关从观察数据(包括可识别性(Pearl的SCM框架))和估计(潜在结果框架)中推断出因果量的不同方法的全面报告。该调查论文的主要贡献是(1)指南,旨在在特定的现实情况下帮助选择合适的公平概念,以及(2)根据Pearl的因果关系阶梯的公平概念的排名,表明它很难部署。实践中的每个概念。
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当经过自动化决策时,决策主题将战略性地修改其可观察特征,他们认为可以最大限度地提高收到理想的结果的机会。在许多情况下,潜在的预测模型是故意保密的,以避免游戏并保持竞争优势。这种不透明度迫使决策主题依赖于制定战略功能修改时依赖不完整的信息。我们将这样的设置捕获作为贝叶斯劝说的游戏,其中决策者发送信号,例如动作建议,以便决定受激励他们采取理想的行动。我们制定决策者找到最佳贝叶斯激励兼容(BIC)行动推荐策略作为优化问题的问题,并通过线性程序表征解决方案。通过这种特征,我们观察到,虽然可以显着地简化了找到最佳BIC推荐策略的问题,但是解决该线性程序的计算复杂性与(1)决策主题的动作空间的相对大小紧密相关(2)基础预测模型利用的特征数。最后,我们提供了最佳BIC推荐政策的性能的界限,并表明与标准基线相比,它可能导致任意更好的结果。
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算法公平吸引了机器学习社区越来越多的关注。文献中提出了各种定义,但是它们之间的差异和联系并未清楚地解决。在本文中,我们回顾并反思了机器学习文献中先前提出的各种公平概念,并试图与道德和政治哲学,尤其是正义理论的论点建立联系。我们还从动态的角度考虑了公平的询问,并进一步考虑了当前预测和决策引起的长期影响。鉴于特征公平性的差异,我们提出了一个流程图,该流程图包括对数据生成过程,预测结果和诱导的影响的不同类型的公平询问的隐式假设和预期结果。本文展示了与任务相匹配的重要性(人们希望执行哪种公平性)和实现预期目的的手段(公平分析的范围是什么,什么是适当的分析计划)。
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Machine learning can impact people with legal or ethical consequences when it is used to automate decisions in areas such as insurance, lending, hiring, and predictive policing. In many of these scenarios, previous decisions have been made that are unfairly biased against certain subpopulations, for example those of a particular race, gender, or sexual orientation. Since this past data may be biased, machine learning predictors must account for this to avoid perpetuating or creating discriminatory practices. In this paper, we develop a framework for modeling fairness using tools from causal inference. Our definition of counterfactual fairness captures the intuition that a decision is fair towards an individual if it is the same in (a) the actual world and (b) a counterfactual world where the individual belonged to a different demographic group. We demonstrate our framework on a real-world problem of fair prediction of success in law school. * Equal contribution. This work was done while JL was a Research Fellow at the Alan Turing Institute. 2 https://obamawhitehouse.archives.gov/blog/2016/05/04/big-risks-big-opportunities-intersection-big-dataand-civil-rights 31st Conference on Neural Information Processing Systems (NIPS 2017),
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我们研究了一个名为“战略MDP”的新型模型下的离线增强学习,该模型表征了本金和一系列与私有类型的近视药物之间的战略相互作用。由于双层结构和私人类型,战略MDP涉及主体与代理之间的信息不对称。我们专注于离线RL问题,其目标是基于由历史互动组成的预采用数据集学习委托人的最佳政策。未观察到的私人类型混淆了这样的数据集,因为它们会影响委托人收到的奖励和观察结果。我们提出了一种新颖的算法,具有算法工具(计划)的悲观政策学习,该算法利用仪器变量回归的思想和悲观主义原则在一般功能近似的背景下学习近乎最佳的原理政策。我们的算法是基于批判性观察,即主体的行为是有效的工具变量。特别是,在离线数据集中的部分覆盖范围假设下,我们证明计划输出$ 1 / \ sqrt {k} $ - 最佳策略,$ k $是收集的轨迹数量。我们进一步将框架应用于一些特殊的战略MDP案例,包括战略回归,战略强盗和推荐系统中的不合规性。
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关于人们的预测,例如他们预期的教育成就或信用风险,可以表现出色,并塑造他们旨在预测的结果。了解这些预测对最终结果的因果影响对于预测未来预测模型的含义并选择要部署哪些模型至关重要。但是,该因果估计任务带来了独特的挑战:模型预测通常是输入特征的确定性功能,并且与结果高度相关,这可能使预测的因果效应不可能从协变量的直接效应中解散。我们通过因果可识别性的角度研究了这个问题,尽管该问题完全普遍,但我们突出了三种自然情况,在这些情况下,可以从观察数据中确定预测对结果的因果影响:基于预测或基于预测的决策中的随机化。 ,在数据收集过程中部署的预测模型和离散预测输出的过度参数化。我们从经验上表明,在适当的可识别性条件下,从预测中预测的监督学习的标准变体可以找到特征,预测和结果之间的可转移功能关系,从而得出有关新部署的预测模型的结论。我们的积极结果从根本上依赖于在数据收集期间记录的模型预测,从而提出了重新思考标准数据收集实践的重要性,以使进步能够更好地理解社会成果和表现性反馈循环。
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估计平均因果效应的理想回归(如果有)是什么?我们在离散协变量的设置中研究了这个问题,从而得出了各种分层估计器的有限样本方差的表达式。这种方法阐明了许多广泛引用的结果的基本统计现象。我们的博览会结合了研究因果效应估计的三种不同的方法论传统的见解:潜在结果,因果图和具有加性误差的结构模型。
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Causal inference is the process of using assumptions, study designs, and estimation strategies to draw conclusions about the causal relationships between variables based on data. This allows researchers to better understand the underlying mechanisms at work in complex systems and make more informed decisions. In many settings, we may not fully observe all the confounders that affect both the treatment and outcome variables, complicating the estimation of causal effects. To address this problem, a growing literature in both causal inference and machine learning proposes to use Instrumental Variables (IV). This paper serves as the first effort to systematically and comprehensively introduce and discuss the IV methods and their applications in both causal inference and machine learning. First, we provide the formal definition of IVs and discuss the identification problem of IV regression methods under different assumptions. Second, we categorize the existing work on IV methods into three streams according to the focus on the proposed methods, including two-stage least squares with IVs, control function with IVs, and evaluation of IVs. For each stream, we present both the classical causal inference methods, and recent developments in the machine learning literature. Then, we introduce a variety of applications of IV methods in real-world scenarios and provide a summary of the available datasets and algorithms. Finally, we summarize the literature, discuss the open problems and suggest promising future research directions for IV methods and their applications. We also develop a toolkit of IVs methods reviewed in this survey at https://github.com/causal-machine-learning-lab/mliv.
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Statistical risk assessments inform consequential decisions such as pretrial release in criminal justice, and loan approvals in consumer finance. Such risk assessments make counterfactual predictions, predicting the likelihood of an outcome under a proposed decision (e.g., what would happen if we approved this loan?). A central challenge, however, is that there may have been unmeasured confounders that jointly affected past decisions and outcomes in the historical data. This paper proposes a tractable mean outcome sensitivity model that bounds the extent to which unmeasured confounders could affect outcomes on average. The mean outcome sensitivity model partially identifies the conditional likelihood of the outcome under the proposed decision, popular predictive performance metrics (e.g., accuracy, calibration, TPR, FPR), and commonly-used predictive disparities. We derive their sharp identified sets, and we then solve three tasks that are essential to deploying statistical risk assessments in high-stakes settings. First, we propose a doubly-robust learning procedure for the bounds on the conditional likelihood of the outcome under the proposed decision. Second, we translate our estimated bounds on the conditional likelihood of the outcome under the proposed decision into a robust, plug-in decision-making policy. Third, we develop doubly-robust estimators of the bounds on the predictive performance of an existing risk assessment.
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Decision makers often aim to learn a treatment assignment policy under a capacity constraint on the number of agents that they can treat. When agents can respond strategically to such policies, competition arises, complicating the estimation of the effect of the policy. In this paper, we study capacity-constrained treatment assignment in the presence of such interference. We consider a dynamic model where the decision maker allocates treatments at each time step and heterogeneous agents myopically best respond to the previous treatment assignment policy. When the number of agents is large but finite, we show that the threshold for receiving treatment under a given policy converges to the policy's mean-field equilibrium threshold. Based on this result, we develop a consistent estimator for the policy effect. In simulations and a semi-synthetic experiment with data from the National Education Longitudinal Study of 1988, we demonstrate that this estimator can be used for learning capacity-constrained policies in the presence of strategic behavior.
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实际上,决策算法通常经过表现出各种偏见的数据培训。决策者通常旨在根据假定或期望公正的基础真相目标做出决策,即同样分布在社会显着的群体中。在许多实际设置中,无法直接观察到地面真相,相反,我们必须依靠数据中的地面真相(即偏置标签)的有偏见的代理度量。此外,通常会选择性地标记数据,即,即使是有偏见的标签,也仅对获得积极决策的数据的一小部分观察到。为了克服标签和选择偏见,最近的工作提议学习随机性,通过i)在每个时间步长的在线培训新政策,ii)执行公平性作为绩效的限制。但是,现有方法仅使用标记的数据,忽略了大量未标记的数据,因此在不同时间学到的决策策略的不稳定性和差异很大。在本文中,我们提出了一种基于实用公平决策的各种自动编码器的新方法。我们的方法学习了一个无偏的数据表示,利用标记和未标记的数据,并使用表示形式在在线过程中学习策略。使用合成数据,我们从经验上验证我们的方法根据差异较低的地面真相会收敛到最佳(公平)策略。在现实世界实验中,我们进一步表明,我们的培训方法不仅提供了更稳定的学习过程,而且还产生了比以前的方法更高的公平性和效用的政策。
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针对社会福利计划中个人的干预措施的主要问题之一是歧视:个性化治疗可能导致跨年龄,性别或种族等敏感属性的差异。本文解决了公平有效的治疗分配规则的设计问题。我们采用了第一次的非遗憾视角,没有危害:我们选择了帕累托边境中最公平的分配。我们将优化投入到混合构成线性程序公式中,可以使用现成的算法来解决。我们对估计的政策功能的不公平性和在帕累托前沿的不公平保证在一般公平概念下的不公平性范围内得出了遗憾。最后,我们使用教育经济学的应用来说明我们的方法。
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公平的机器学习研究人员(ML)围绕几个公平标准结合,这些标准为ML模型公平提供了正式的定义。但是,这些标准有一些严重的局限性。我们确定了这些正式公平标准的四个主要缺点,并旨在通过扩展性能预测以包含分配强大的目标来帮助解决这些问题。
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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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In the classical setting of self-selection, the goal is to learn $k$ models, simultaneously from observations $(x^{(i)}, y^{(i)})$ where $y^{(i)}$ is the output of one of $k$ underlying models on input $x^{(i)}$. In contrast to mixture models, where we observe the output of a randomly selected model, here the observed model depends on the outputs themselves, and is determined by some known selection criterion. For example, we might observe the highest output, the smallest output, or the median output of the $k$ models. In known-index self-selection, the identity of the observed model output is observable; in unknown-index self-selection, it is not. Self-selection has a long history in Econometrics and applications in various theoretical and applied fields, including treatment effect estimation, imitation learning, learning from strategically reported data, and learning from markets at disequilibrium. In this work, we present the first computationally and statistically efficient estimation algorithms for the most standard setting of this problem where the models are linear. In the known-index case, we require poly$(1/\varepsilon, k, d)$ sample and time complexity to estimate all model parameters to accuracy $\varepsilon$ in $d$ dimensions, and can accommodate quite general selection criteria. In the more challenging unknown-index case, even the identifiability of the linear models (from infinitely many samples) was not known. We show three results in this case for the commonly studied $\max$ self-selection criterion: (1) we show that the linear models are indeed identifiable, (2) for general $k$ we provide an algorithm with poly$(d) \exp(\text{poly}(k))$ sample and time complexity to estimate the regression parameters up to error $1/\text{poly}(k)$, and (3) for $k = 2$ we provide an algorithm for any error $\varepsilon$ and poly$(d, 1/\varepsilon)$ sample and time complexity.
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分类,一种重大研究的数据驱动机器学习任务,驱动越来越多的预测系统,涉及批准的人类决策,如贷款批准和犯罪风险评估。然而,分类器经常展示歧视性行为,特别是当呈现有偏置数据时。因此,分类公平已经成为一个高优先级的研究区。数据管理研究显示与数据和算法公平有关的主题的增加和兴趣,包括公平分类的主题。公平分类的跨学科努力,具有最大存在的机器学习研究,导致大量的公平概念和尚未系统地评估和比较的广泛方法。在本文中,我们对13个公平分类方法和额外变种的广泛分析,超越,公平,公平,效率,可扩展性,对数据误差的鲁棒性,对潜在的ML模型,数据效率和使用各种指标的稳定性的敏感性和稳定性现实世界数据集。我们的分析突出了对不同指标的影响的新颖见解和高级方法特征对不同方面的性能方面。我们还讨论了选择适合不同实际设置的方法的一般原则,并确定以数据管理为中心的解决方案可能产生最大影响的区域。
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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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