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arXiv 0901.4011stat.AP
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Logistic和其他回归模型的弱信息缺省先验分布

A weakly informative default prior distribution for logistic and other regression models

Andrew Gelman, Aleks Jakulin, Maria Grazia Pittau, Yu-Sung Su

摘要:

我们提出了一个新的先验分布的经典(nonhierarchical)逻辑斯谛回归模型,构造的第一次缩放所有非二进制变量的均值为0和标准差为0.5,然后放置独立的学生$t$先验分布的系数。作为默认选择,我们推荐中心为0、标度为2.5的柯西分布,在最简单的设置中,它是通过假设逻辑斯谛回归中有一半额外成功和一半额外失败而获得的分布的长尾版本。在数据集语料库上的交叉验证表明,柯西类的先验分布优于高斯和拉普拉斯先验的现有实现。我们建议将此先验分布作为常规应用的默认选择。它的优点是总是给出答案,即使在逻辑斯谛回归中存在完全分离(这是一个常见的问题,即使样本量很大,预测因子的数量很小),并且还自动将更多的收缩应用于高阶相互作用。这在常规数据分析以及自动化程序(如缺失数据插补的链式方程)中非常有用。通过将近似期望最大化算法结合到通常的迭代加权最小二乘法中,我们实现了一个过程来拟合R中的广义线性模型与$t$先验分布。我们说明了几个应用程序,包括一系列的逻辑斯谛回归预测投票偏好,一个小的生物测定实验,和一个公共卫生数据集的插补模型。

英文摘要:

We propose a new prior distribution for classical (nonhierarchical) logistic regression models, constructed by first scaling all nonbinary variables to have mean 0 and standard deviation 0.5, and then placing independent Student-$t$ prior distributions on the coefficients. As a default choice, we recommend the Cauchy distribution with center 0 and scale 2.5, which in the simplest setting is a longer-tailed version of the distribution attained by assuming one-half additional success and one-half additional failure in a logistic regression. Cross-validation on a corpus of datasets shows the Cauchy class of prior distributions to outperform existing implementations of Gaussian and Laplace priors. We recommend this prior distribution as a default choice for routine applied use. It has the advantage of always giving answers, even when there is complete separation in logistic regression (a common problem, even when the sample size is large and the number of predictors is small), and also automatically applying more shrinkage to higher-order interactions. This can be useful in routine data analysis as well as in automated procedures such as chained equations for missing-data imputation. We implement a procedure to fit generalized linear models in R with the Student-$t$ prior distribution by incorporating an approximate EM algorithm into the usual iteratively weighted least squares. We illustrate with several applications, including a series of logistic regressions predicting voting preferences, a small bioassay experiment, and an imputation model for a public health data set.

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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