We study critical systems that allocate scarce resources to satisfy basic needs, such as homeless services that provide housing. These systems often support communities disproportionately affected by systemic racial, gender, or other injustices, so it is crucial to design these systems with fairness considerations in mind. To address this problem, we propose a framework for evaluating fairness in contextual resource allocation systems that is inspired by fairness metrics in machine learning. This framework can be applied to evaluate the fairness properties of a historical policy, as well as to impose constraints in the design of new (counterfactual) allocation policies. Our work culminates with a set of incompatibility results that investigate the interplay between the different fairness metrics we propose. Notably, we demonstrate that: 1) fairness in allocation and fairness in outcomes are usually incompatible; 2) policies that prioritize based on a vulnerability score will usually result in unequal outcomes across groups, even if the score is perfectly calibrated; 3) policies using contextual information beyond what is needed to characterize baseline risk and treatment effects can be fairer in their outcomes than those using just baseline risk and treatment effects; and 4) policies using group status in addition to baseline risk and treatment effects are as fair as possible given all available information. Our framework can help guide the discussion among stakeholders in deciding which fairness metrics to impose when allocating scarce resources.

在高风险领域（人们的生计受到影响）中，机器学习的日益增长的使用迫切需要解释和公平的算法。在这些设置中，此类算法的准确性也至关重要。考虑到这些需求，我们提出了一个混合整数优化（MIO）框架，用于学习具有固定深度的最佳分类树，可以通过任意域特定的公平约束来方便地增强。我们基于在流行数据集上建造公平树木的最先进方法基准测试；鉴于固定的歧视阈值，我们的方法平均将样本外（OOS）的精度提高了2.3个百分点，并在88.9％的实验上获得了更高的OOS精度。我们还将各种算法公平概念纳入我们的方法中，展示其多功能建模能力，使决策者可以微调准确性和公平性之间的权衡。

我们研究了通过中等数量的成对比较查询引发决策者偏好的问题，以使它们成为特定问题的高质量推荐。我们受到高赌场域中的应用程序的推动，例如选择分配稀缺资源的政策以满足基本需求（例如，用于移植或住房的肾脏，因为那些经历无家可归者），其中需要由（部分）提出引出的偏好。我们在基于偏好的偏好中模拟不确定性，并调查两个设置：a）脱机偏出设置，其中所有查询都是一次，b）在线诱因设置，其中按时间顺序选择查询。我们提出了这些问题的强大优化制剂，这些问题集成了偏好诱导和推荐阶段，其目的是最大化最坏情况的效用或最小化最坏情况的后悔，并研究其复杂性。对于离线案例，在活动偏好诱导与决策信息发现的两个半阶段的稳健优化问题的形式中，我们提供了我们通过列解决的混合二进制线性程序的形式提供了等效的重构。 -Constraint生成。对于在线设置，主动偏好学习采用多级强大优化问题的形式与决策依赖的信息发现，我们提出了一种保守的解决方案方法。合成数据的数值研究表明，我们的方法在最坏情况级别，后悔和效用方面从文献中倾斜最先进的方法。我们展示了我们的方法论如何用于协助无家可归的服务机构选择分配不同类型的稀缺住房资源的政策，以遇到无家可归者。