Reducing sample size needed for cox-proportional hazards model analysis using more efficient sampling method

Abstract

In general, survival data are time-to-event data, such as time to death, time to appearance of a tumor, or time to recurrence of a disease. Models for survival data have frequently been based on the proportional hazards model, proposed by Cox. The Cox model has intensive application in the field of social, medical, behavioral and public health sciences. In this paper we propose a more efficient sampling method of recruiting subjects for survival analysis. We propose using a Moving Extreme Ranked Set Sampling (MERSS) scheme with ranking based on an easy-to-evaluate baseline auxiliary variable known to be associated with survival time. This paper demonstrates that this approach provides a more powerful testing procedure as well as a more efficient estimate of hazard ratio than that based on simple random sampling (SRS). Theoretical derivation and simulation studies are provided. The Iowa 65+ Rural study data are used to illustrate the methods developed in this paper.     

英国的刑事上诉制度研究

英国对刑事案件基本上实行两级上诉制度 :对于刑事法院的一审裁判可以依次向上诉法院和上议院上诉 ;对治安法院的裁判 ,可以分别向刑事法院或者高等法院以及上议院上诉 ,但是 ,二者的程序规则不完全相同。2 0世纪 70年代以来 ,英国上诉制度逐渐向大陆法系靠拢 ,最近英国政府再次提议进一步扩大控诉方的上诉权 ,英国上诉制度可能将发生重大变化。     

加强高校校园文化建设是加强和改进高校思想政治教育的重要途径

高校校园文化是高校物质财富和精神财富的总称。高校校园文化具有强大的育人功能:它以物质为载体,以制度为保障,以实践活动为形式,以先进的教育理念引导师生,以丰富的校园文化内涵塑造师生;它能陶冶人们的情操,磨练人们的意志,丰富人们的智慧,增添人们的生活情趣。高校校园文化是高校教书育人、管理育人、服务育人和环境育人的集中体现。加强高校校园文化建设是加强和改进新时期高校思想政治教育的重要途径。     

反思叛逆,企盼理性——《失乐园》主题探微

弥尔顿诗作《失乐园》的主题是复式开放性的 ,历来众说纷纭。本文从历史、宗教和人性的角度 ,重新审视它的主题 ,认为反思叛逆、企盼理性正是诗人在《失乐园》创作中力图体现的深刻主题。     

英国新工党与社会民主党:政策趋同与差异

20世纪90年代以后,经济全球化促使包括英国工党在内的欧洲左派政党出现前所未有的趋同,从经济政策到社会政策等,各国虽有差距,但无疑出现了巨大的共识。同时,由于各国背景不同,英国新工党的反应及相应措施与其他政党仍存在一定的分歧。工党与其他社会民主党对平等和充分就业的理解不同,各党则呈现出复杂的政策差异。这些政策差异及随后国际和欧洲环境的变化,必然导致第三条道路在一阵炒作之后冷却下来。     

Fitting competing risks data to bivariate Pareto models

This paper revisits two bivariate Pareto models for fitting competing risks data. The first model is the Frank copula model, and the second one is a bivariate Pareto model introduced by Sankaran and Nair (1993 Sankaran, P. G., and N. U. Nair. 1993. A bivariate Pareto model and its applications to reliability. Naval Research Logistics 40 (7):1013–1020. doi:10.1002/1520-6750(199312)40:7%3c1013::AID-NAV3220400711%3e3.0.CO;2-7.[Crossref], [Web of Science ®] , [Google Scholar]). We discuss the identifiability issues of these models and develop the maximum likelihood estimation procedures including their computational algorithms and model-diagnostic procedures. Simulations are conducted to examine the performance of the maximum likelihood estimation. Real data are analyzed for illustration.     

论新媒体冲击下纸媒的生存与发展——以报纸为例

互联网的发展、智能手机的普及使传统的传媒环境和格局发生了翻天覆地的变化。新媒体的崛起与壮大给以纸媒为代表的传统媒体带来了前所未有的冲击，但不可否认的是，纸媒自身依然有不可替代的优势。本文主要以报纸为例，从纸媒传播内容的深度和可信度、纸媒对于受众文化素质的要求以及纸媒的表现形式、和受众的互动等方面的特点入手，分析在新媒体的冲击下纸媒所面临的生存现状，并且在此基础上指出将来纸媒应该如何利用新媒体的技术来促进自身的发展，更好地实现新媒体与传统媒体的融合。     

A goodness of fit test for multilevel survival data

No satisfactory goodness of fit test is available for multilevel survival data which occur when survival data are clustered or hierarchical in nature. Hence the aim of this research is to develop a new goodness of fit test for multilevel survival data and to examine the properties of the newly developed test. Simulation studies were carried out to evaluate the type ? error and the power. The results showed that the type I error holds for every combination tested and that the test is powerful against the alternative hypothesis of nonproportional hazards for all combinations tested.     

综述和讨论:关于小民族的生存及前景

作为人类社会、人类文化重要组成部分的小民族的生存及未来前景问题,他们因传统文化特点、因外部社会因素而引发的带有小民族特有特点的现实生存难题,早已引起人类学以及相关学科的高度重视,我国近些年对国内小民族的研究也渐成气象。那么,国内就小民族生存、发展问题的关注和实证研究状况如何?近数十年来,整个学界围绕小民族生存和未来前景以及影响因素的探讨,主要关注了哪些层面?提出了哪些主要观点?从问题意识出发,并结合自己有限的田野工作经验,本文尝试进行初步的综述和讨论。     

Semiparametric Estimation of a Change-point for Recurrent Events Data

One particular recurrent events data scenario involves patients experiencing events according to a common intensity rate, and then a treatment may be applied. The treatment might be effective for a limited amount of time, so that the intensity rate would be expected to change abruptly when the effect of the treatment wears out. In particular, we allow models for the intensity rate, post-treatment, to be at first decreasing and then change to increasing (and vice versa). Two estimators of the location of this change are proposed.