Estimation of the additive hazards model with interval-censored data and missing covariates

The additive hazards model is one of the most commonly used regression models in the analysis of failure time data and many methods have been developed for its inference in various situations. However, no established estimation procedure exists when there are covariates with missing values and the observed responses are interval-censored; both types of complications arise in various settings including demographic, epidemiological, financial, medical and sociological studies. To address this deficiency, we propose several inverse probability weight-based and reweighting-based estimation procedures for the situation where covariate values are missing at random. The resulting estimators of regression model parameters are shown to be consistent and asymptotically normal. The numerical results that we report from a simulation study suggest that the proposed methods work well in practical situations. An application to a childhood cancer survival study is provided. The Canadian Journal of Statistics 48: 499–517; 2020 © 2020 Statistical Society of Canada     

关于高校中层副职干部几个基本问题的思考

高校中层副职干部具有高校干部、中层干部和副职干部的群体特征，应当具备相应的政治、思想、道德、业务、能力和身体等方面的基本素质。高校应当按照现行干部配置规制，结合内部管理体制和工作机制任用干部。高校中层副职干部的日常活动涉及到社会、学校、家庭等多个层面，必须妥善处理好各种人事关系。     

面向汉语国际教育的记号字研究

在《汉语国际教育用音节汉字词汇等级划分》的3000汉字中,记号字占将近六分之一的比例,主要分布在一级、二级汉字中,其中在一级汉字中占绝对优势。记号字来源于六书中的象形字、会意字、形声字、指事字,也来源于半意半记字、音零字和记号字。在汉字形体演变的过程中,现今的记号字是由于笔形之变、结构之变和功能之变等诸多因素形成的,因此对记号字的认知也是分层次的,可以从文字学角度和非字源角度分别认知。     

Testing equality of two normal covariance matrices with monotone missing data

Abstract

The problem of testing equality of two multivariate normal covariance matrices is considered. Assuming that the incomplete data are of monotone pattern, a quantity similar to the Likelihood Ratio Test Statistic is proposed. A satisfactory approximation to the distribution of the quantity is derived. Hypothesis testing based on the approximate distribution is outlined. The merits of the test are investigated using Monte Carlo simulation. Monte Carlo studies indicate that the test is very satisfactory even for moderately small samples. The proposed methods are illustrated using an example.     

Simultaneous edit-imputation and disclosure limitation for business establishment data

Business establishment microdata typically are required to satisfy agency-specified edit rules, such as balance equations and linear inequalities. Inevitably some establishments' reported data violate the edit rules. Statistical agencies correct faulty values using a process known as edit-imputation. Business establishment data also must be heavily redacted before being shared with the public; indeed, confidentiality concerns lead many agencies not to share establishment microdata as unrestricted access files. When microdata must be heavily redacted, one approach is to create synthetic data, as done in the U.S. Longitudinal Business Database and the German IAB Establishment Panel. This article presents the first implementation of a fully integrated approach to edit-imputation and data synthesis. We illustrate the approach on data from the U.S. Census of Manufactures and present a variety of evaluations of the utility of the synthetic data. The paper also presents assessments of disclosure risks for several intruder attacks. We find that the synthetic data preserve important distributional features from the post-editing confidential microdata, and have low risks for the various attacks.     

滇南彝族传统经籍文学的主要类型和特点

滇南彝族传统经籍文学是当地彝族历代毕摩在当地彝族民间口传文学的基础上,用本民族传统文字——彝文如实记录、第二次创作以及翻译转写其他民族民间文学,并由彝族毕摩一代又一代不断加工、修改、补充、完善,且流传至今的滇南彝族传统经籍文学。从当地历代彝族毕摩所保护和传承且当地彝族民间流传的传统经籍文学版本的主要体裁、素材及其内容看,有史诗类、传说类、伦理类、神灵传言类、婚丧礼仪类、恋爱婚姻类及译著类等;又从当今当地彝族毕摩讲唱传承形式和场域及其采用的唱腔唱曲音乐看,有“甲苏甲类”“诺依特类”“设依甲类”“阿哩甲类”等。纵观滇南彝族传统经籍文学主要体裁、素材及其内容,具有民族性与国际性、支系性与区域性、原生性与变异性、追忆性与憧憬性、丰富性与复杂性、吸纳性与开放性、祭祀性与文学性、历史性与时代性等主要特点。     

Skew-normal factor analysis models with incomplete data

Traditional factor analysis (FA) rests on the assumption of multivariate normality. However, in some practical situations, the data do not meet this assumption; thus, the statistical inference made from such data may be misleading. This paper aims at providing some new tools for the skew-normal (SN) FA model when missing values occur in the data. In such a model, the latent factors are assumed to follow a restricted version of multivariate SN distribution with additional shape parameters for accommodating skewness. We develop an analytically feasible expectation conditional maximization algorithm for carrying out parameter estimation and imputation of missing values under missing at random mechanisms. The practical utility of the proposed methodology is illustrated with two real data examples and the results are compared with those obtained from the traditional FA counterparts.     

重庆方言本字小考

文章主要依据音义结合的方法,考证重庆方言中部分口语词之本字。     

Handling Missing Values in Longitudinal Panel Data With Multiple Imputation

This article offers an applied review of key issues and methods for the analysis of longitudinal panel data in the presence of missing values. The authors consider the unique challenges associated with attrition (survey dropout), incomplete repeated measures, and unknown observations of time. Using simulated data based on 4 waves of the Marital Instability Over the Life Course Study (n = 2,034), they applied a fixed effect regression model and an event‐history analysis with time‐varying covariates. They then compared results for analyses with nonimputed missing data and with imputed data both in long and in wide structures. Imputation produced improved estimates in the event‐history analysis but only modest improvements in the estimates and standard errors of the fixed effects analysis. Factors responsible for differences in the value of imputation are examined, and recommendations for handling missing values in panel data are presented.