Empirical risk minimization (ERM) is typically designed to perform well on the average loss, which can result in estimators that are sensitive to outliers, generalize poorly, or treat subgroups unfairly. While many methods aim to address these problems individually, in this work, we explore them through a unified framework---tilted empirical risk minimization (TERM). In particular, we show that it is possible to flexibly tune the impact of individual losses through a straightforward extension to ERM using a hyperparameter called the tilt. We provide several interpretations of the resulting framework: We show that TERM can increase or decrease the influence of outliers, respectively, to enable fairness or robustness; has variance-reduction properties that can benefit generalization; and can be viewed as a smooth approximation to a superquantile method. We develop batch and stochastic first-order optimization methods for solving TERM, and show that the problem can be efficiently solved relative to common alternatives. Finally, we demonstrate that TERM can be used for a multitude of applications, such as enforcing fairness between subgroups, mitigating the effect of outliers, and handling class imbalance. TERM is not only competitive with existing solutions tailored to these individual problems, but can also enable entirely new applications, such as simultaneously addressing outliers and promoting fairness.

本文提出了一种名为tilted empirical risk minimization (TERM)的新框架，通过引入一个称之为tilt的超参数，它能够灵活调整每个个体损失的影响，以实现对离群点的鲁棒性或公平性，同时具有减少方差，促进泛化和处理类别不平衡的能力。我们通过发展批和随机一阶优化方法来解决TERM问题，并证明它相对于常见的替代方案，能够高效地解决这个问题。除了在现有解决方案这些问题，提出方案竞争力之外，我们还将TERM用于多种应用，如在亚组之间实施公平性，减轻离群值的影响以及处理类别失衡问题。

倾斜的经验风险最小化