A scoring rule is a loss function measuring the quality of a quoted probability distribution $Q$ for a random variable $X$, in the light of the realized outcome $x$ of $X$; it is proper if the expected score, under any distribution $P$ for $X$, is minimized by quoting $Q=P$. Using the fact that any differentiable proper scoring rule on a finite sample space ${\mathcal{X}}$ is the gradient of a concave homogeneous function, we consider when such a rule can be local in the sense of depending only on the probabilities quoted for points in a nominated neighborhood of $x$. Under mild conditions, we characterize such a proper local scoring rule in terms of a collection of homogeneous functions on the cliques of an undirected graph on the space ${\mathcal{X}}$. A useful property of such rules is that the quoted distribution $Q$ need only be known up to a scale factor. Examples of the use of such scoring rules include Besag's pseudo-likelihood and Hyvärinen's method of ratio matching.
Learning high-dimensional graphical models with regularized quadratic scoring
成对马尔可夫随机场(MRF)或无向图形模型是联合概率分布的简约表示。变量对应于图的节点,节点之间的边对应于条件依赖性。不幸的是,基于似然的学习和推理受到难以计算的归一化常数的阻碍。本文考虑了对数似然的另一种评分规则,它避免了需要计算分布的归一化常数。我们表明,该规则是一个二次函数的自然参数。我们优化这个评分规则和稀疏诱导正则化的总和。对于一般的连续值指数族,我们给出了参数和边相容性的理论结果。作为特例,我们详细介绍了一种新的稀疏精度矩阵估计方法,其理论保证与Yuan和Lin(2007)的图形套索相匹配,计算性能比Yuan(2010)的glasso算法更快。然后,我们描述了使用指数序列的非参数成对图模型中的模型选择结果。正则化分数匹配问题被证明是一个凸规划;我们提供了基于乘法器的共识交替方向法(Boyd et al.(2011))和坐标下降的可扩展算法。
Generative Adversarial Nets for Robust Scatter Estimation: A Proper Scoring Rule Perspective
University of Chicago(芝加哥大学);Hong Kong University of Science and Technology(香港科技大学)
稳健散布估计是统计学中的一项基本任务。Gao et al.(2018)最近关于鲁棒估计和生成对抗网络(GANs)之间的联系的发现表明,可以使用优化GANs的类似技术来计算类似深度的鲁棒估计器。在本文中,我们介绍了一个一般的学习通过分类框架的基础上适当的评分规则的概念。这个框架允许我们通过$f$的变分近似的透镜来理解矩阵深度函数和各种GANs-由适当的评分规则引起的发散。然后,我们提出了一类新的强大的散布估计在这个框架中仔细构造鉴别器与适当的神经网络结构。在Huber污染模型下,证明了这些估计量能达到极小极大散布率估计.我们的数值结果表明,在各种设置下对文献中的竞争对手的良好性能。
When Are Scoring Rules Proper? Bridging Theory and Practice in Survival Model Evaluation
Department of Cancer Genetics, Institute for Cancer Research, Oslo University Hospital(癌症遗传学系,癌症研究所,奥斯陆大学医院);Department of Biostatistics, Faculty of Medicine, Oslo Centre for Biostatistics and Epidemiology (OCBE), University of Oslo, Norway(生物统计学系,医学学院,奥斯陆生物统计与流行病学中心(OCBE),奥斯陆大学,挪威);OSPO Now, London, UK(伦敦,英国OSPO Now);Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Oslo, Norway(数学系,数学与自然科学学院,奥斯陆大学,挪威);Department of Statistics, LMU Munich, Germany(统计学系,慕尼黑大学);Munich Center for Machine Learning (MCML), LMU Munich, Germany(慕尼黑机器学习中心(MCML),慕尼黑大学,德国);Statistical Consulting Unit (StaBLab), LMU Munich, Germany(统计咨询单位(StaBLab),慕尼黑大学,德国);Leibniz Institute for Prevention Research and Epidemiology - BIPS, Bremen, Germany(预防研究与流行病学研究所—BIPS,不莱梅,德国);Faculty of Mathematics and Computer Science, University of Bremen, Germany(数学与计算机科学学院,不莱梅大学,德国)