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arXiv 2212.05565stat.MEmath.STstat.TH
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多变量期望损失回归的稳健估计与推断

Robust Estimation and Inference for Expected Shortfall Regression with Many Regressors

Xuming He, Kean Ming Tan, Wen-Xin Zhou

摘要:

期望短缺(Expected Shortfall,ES),又称超分位数或条件风险值,是风险分析和随机最优化中的重要度量,并在其他领域得到了广泛应用。在金融中,它指的是资产的条件预期回报,假设回报低于其分布的某个分位数。在本文中,我们考虑了最近提出的联合回归框架,同时模拟的分位数和ES的响应变量给定一组协变量,最先进的方法是基于最小化的联合损失函数,是不可微的和非凸的。这不可避免地带来了数值挑战,并限制了其分析大规模数据的适用性。出于使用奈曼正交分数的想法,以减少灵敏度方面的滋扰参数,我们提出了一个统计上强大的(高度倾斜和重尾数据)和计算效率高的两步程序拟合联合分位数和ES回归模型。随着协变量维数的增加,我们建立了估计和高斯近似误差的显式非渐近界,这为统计推断奠定了基础。最后,我们通过数值实验和两个数据应用程序证明,我们的方法很好地平衡了预期短缺回归的鲁棒性,统计和数值效率。

英文摘要:

Expected Shortfall (ES), also known as superquantile or Conditional Value-at-Risk, has been recognized as an important measure in risk analysis and stochastic optimization, and is also finding applications beyond these areas. In finance, it refers to the conditional expected return of an asset given that the return is below some quantile of its distribution. In this paper, we consider a recently proposed joint regression framework that simultaneously models the quantile and the ES of a response variable given a set of covariates, for which the state-of-the-art approach is based on minimizing a joint loss function that is non-differentiable and non-convex. This inevitably raises numerical challenges and limits its applicability for analyzing large-scale data. Motivated by the idea of using Neyman-orthogonal scores to reduce sensitivity with respect to nuisance parameters, we propose a statistically robust (to highly skewed and heavy-tailed data) and computationally efficient two-step procedure for fitting joint quantile and ES regression models. With increasing covariate dimensions, we establish explicit non-asymptotic bounds on estimation and Gaussian approximation errors, which lay the foundation for statistical inference. Finally, we demonstrate through numerical experiments and two data applications that our approach well balances robustness, statistical, and numerical efficiencies for expected shortfall regression.

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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