Non-ignorable missing covariate data in survival analysis: a case-study of an International Breast Cancer Study Group trial

Summary.  Non-ignorable missing data, a serious problem in both clinical trials and observational studies, can lead to biased inferences. Quality-of-life measures have become increasingly popular in clinical trials. However, these measures are often incompletely observed, and investigators may suspect that missing quality-of-life data are likely to be non-ignorable. Although several recent references have addressed missing covariates in survival analysis, they all required the assumption that missingness is at random or that all covariates are discrete. We present a method for estimating the parameters in the Cox proportional hazards model when missing covariates may be non-ignorable and continuous or discrete. Our method is useful in reducing the bias and improving efficiency in the presence of missing data. The methodology clearly specifies assumptions about the missing data mechanism and, through sensitivity analysis, helps investigators to understand the potential effect of missing data on study results.     

ASSESSING CONGRUENCEAMONG DISTANCE MATRICES: SINGLE-MALT SCOTCH WHISKIES REVISITED

A test of congruence among distance matrices is described. It tests the hypothesis that several matrices, containing different types of variables about the same objects, are congruent with one another, so they can be used jointly in statistical analysis. Raw data tables are turned into similarity or distance matrices prior to testing; they can then be compared to data that naturally come in the form of distance matrices. The proposed test can be seen as a generalization of the Mantel test of matrix correspondence to any number of distance matrices. This paper shows that the new test has the correct rate of Type I error and good power. Power increases as the number of objects and the number of congruent data matrices increase; power is higher when the total number of matrices in the study is smaller. To illustrate the method, the proposed test is used to test the hypothesis that matrices representing different types of organoleptic variables (colour, nose, body, palate and finish) in single‐malt Scotch whiskies are congruent.     

Robustness of a Class of Partial Diallel Cross Designs to the Unavailability of a Complete Block of Observations

Complete and partial diallel cross designs are examined as to their construction and robustness against the loss of a block of observations. A simple generalized inverse is found for the information matrix of the line effects, which allows evaluation of expressions for the variances of the line-effect differences with and without the missing block. A-efficiencies, based on average variances of the elementary contrasts of the line-effects, suggest that these designs are fairly robust. The loss of efficiency is generally less than 10%, but it is shown that specific comparisons might suffer a loss of efficiency of as much as 40%.     

试论扩招后高校社会治安综合治理

通过对学校社会治安状况的调研,弄清校园及周边社会治安综合治理的重点、难点;分析其普遍性和特殊性;弄清校园及周边人、财、物的动态平衡关系,着力提高防范能力,以便对校园及周边实施科学管理,降低治理成本。运用辩证唯物主义的立场、观点和方法掌握其规律性,有针对性地解决高校扩招后学校社会治安综合治理工作的问题,有力保证学校教学、科研工作,从而促进高校改革的顺利进行,为当地政府和学校领导提供高校扩招后学校社会治安综合治理工作的决策依据。     

职业地位取得的社会性别差异

本文从描述被调查夫妇之间职业流动的性别差异出发，分别勾画出他们的地位实现模型。首先验证了不论性别，教育地位都是决定职业地位实现的首要变量；但也正是在教育地位的实现和向上流动(再求学)中，伴随婚姻生育等生命事件的发生，无形的结构性制度因素(意识形态层面的性别制度、性别规范和性别文化)正如后现代主义试图解构的那样依然支配着性别角色的社会化和继续社会化，使扮演双重角色的妻子或无意识地或有意识地遭遇了丈夫不为之所累的两难困境，并最终阻碍了女性的教育地位、既而是职业地位的实现。本文最后提出了三点建议和几个尚待解决的问题。     

创设良好氛围 培养学生的创新精神

作为培养人才的摇篮,学校要积极培养具有创新精神的人才.小学语文教学的良好氛围有助于培养学生的创新精神.良好氛围包括民主平等、以学生为主体、激励求异、启发探索、积极评价等.     

人大代表对公民意识的影响

民主政治与公民意识关联互动,在这种互动中,精英分子有着重要的影响。在人民代表大会制度中,人大代表理应是民主政治的精英分子,他们的意识和行为对公民意识的影响不容忽视,因此要提高人大代表的素质,强化这种影响。     

地力山土族生计方式与家庭经济结构

地力山是甘南藏族自治州卓尼县杓哇土族乡的一个纯土族自然村。由于特定的历史、自然和社会原因,形成了以农为主牧业为辅的传统生计方式。随着时代的变化,兼事务工成为了传统生计方式的补充。在地力山土族家庭经济过程中,生计方式支配着资源要素的投入方向,而资源要素在不同方向上的配置最终构成其家庭经济的各个形态,形态之间以及具体形态内部存在的动态性,为其进一步调整提供了内在条件。     

统计执法的博弈分析

针对目前中国统计数据失真相当严重并引起社会各界普遍关注的现象，运用博弈论作为分析工具，引入重复博弈研究了统计执法中数据报方与查方的利益冲突关系，从统计执法的角度揭示了统计数据失真的主要原因，并提出了相应的五项对策。     

加强高校课程建设的基本途径

目前,高校课程建设存在诸多问题,为此必须健全和完善课程建设的有效途径。本文从建立健全竞争机制、调动教师积极性,建立健全教学质量监控体系,加强课程实践基地建设等方面,阐述了高校课程建设的基本途径。