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.     

The intergenerational education spillovers of pension reform in China

Economic theory establishes that pension privatization weakens the link between old and young and so reduces the incentive to invest in public education in an economy with lower return rate of capital than growth rate of wage. However, empirical studies of the link change are few. In this paper, we investigate the effects of pension privatization and the central government’s subsidy to individual accounts on public education spending in a three-period overlapping generation model. And then, we take contemporary pension reforms in a number of Chinese provinces as offering natural experiment conditions. Using a difference-in-difference framework and 282 municipal districts panel data over years 1998–2009, we test the pension-education theoretical link change. Both our theoretical and empirical results confirm that pension privatization is adversely associated with local public spending on education in China. Private pension subsidies, moreover, magnify this effect. Our study supports the theoretical assertion and selective empirical findings of a negative intergenerational effect of pension privatization.     

A majorization comparison of apportionment methods in proportional representation

From the inception of the proportional representation movement it has been an issue whether larger parties are favored at the expense of smaller parties in one apportionment of seats as compared to another apportionment. A number of methods have been proposed and are used in countries with a proportional representation system. These apportionment methods exhibit a regularity of order, as discussed in the present paper, that captures the preferential treatment of larger versus smaller parties. This order, namely majorization, permits the comparison of seat allocations in two apportionments. For divisor methods, we show that one method is majorized by another method if and only if their signpost ratios are increasing. This criterion is satisfied for the divisor methods with power-mean rounding, and for the divisor methods with stationary rounding. Majorization places the five traditional apportionment methods in the order as they are known to favor larger parties over smaller parties: Adams, Dean, Hill, Webster, and Jefferson. Received: 5 August 2000/Accepted: 24 October 2001     

Worlds come apart: Systems theory versus critical theory. Drama in the history of sociology in the twentieth century

This article places an episode in the history of sociological theory into intellectual history in the twentieth century. The perspective is chronological as well as contextual. The themes are two theoretical approaches, both embedded in both American and German history, Parsonian Systems Theory and “Frankfurt School” Critical Theory. The chronology shown spanned mainly from the 1940s to the 1960s. The context of the two theories is a period that is crucial in twentieth century history. The protagonists of the two approaches were, in the 1940s, Americans and Germans exiled in the United States. In the 1950s, both approaches were affected by McCarthyism in different ways. The 1960s, however, were the culmination. The dynamics of the two approaches led into a schism which came into the open on the occasion of the 1964 German Sociology Conference in Heidelberg celebrating Max Weber. The article shows the stages in the evolution of the schism, emulating three acts in a drama. The final split was over whether Weber or Marx should be the classic whose oeuvre was to influence sociological thinking today. My aim is to exemplify how these two authoritative approaches in sociological theory, far from escaping the vagaries and vicissitudes of their times, were embedded in twentieth-century history.     

Partial strikes under the railway labor act: The need for a doctrine of unprotected concerted activity

In light of use by airline unions of partial-strike tactics, such as concerted refusals to bid for overtime work and so-called ” CHAOS” tactics involving unannounced refusals to fly after passengers have been ticketed and are ready to board, the authors examine whether the Railway Labor Act (RLA) should be interpreted to permit employers to discipline employees for engaging in such tactics, or whether these are a protected form of economic pressure. Although in many respects bargaining duties and economic weapons under the RLA are read consonant with precedents under the National Labor Relations Act (NLRA) (which governs all industries other than rail and air transport), there are a few decisions suggesting that during the period when self-help may be resorted to, employees can engage in partial strike activities as long as they violate no court order but are subject to permanent replacement in limited circumstances. These decisions, the authors submit, fail to take account of Supreme Court decsions since the 1930s that some economic pressures by unions, such as slowdowns and sitins, may not violate the labor laws but nor are they protected by those laws so as to immunize partial strikers from employer discipline. These decisions are not based on unique features of the NLRA. Rather, they give recognition to the background assumptions of Congress that employers may act to protect their property interests as long as they do not run afoul of NLRA or RLA protections and that employees who engage in partial-strike activities are subject to employer discipline even where not strictly necessary to maintain operations. Moreover, these tactics skew the bargaining process by giving employees an essentially risk-free gambit to pressure their economic position through planned disruption of carrier operations. Professor Estreicher is also labor and employment counsel to O’Melveny & Myers, LLP. The views expressed herein are the authors’ and should not be attributed to any organization. Hannah Breshin and Tom Jerman of O’Melveny & Myers, assisted the authors with this article. We also thank Professor Herbert Northrup for his helpful comments.     

腔内电光调制激光系统的混沌模拟

采用数值模拟的方法讨论了带反馈的腔內电光调制激光系统功率输出的分叉和混沌行为,得到了输出功率随控制参数变化的分叉图,和一些定量结果。     

用联想神经网络设计的信道均衡器

研究了联想神经网络在数字通信信道均衡器实现中的应用,讨论了其设计方法和设计步骤,给出了计算机模拟结果,并进行了性能比较。研究结果表明:Hopfield联想神经网络实现的信道均衡器具有比传统线性横向均衡器更优越的性能。     

从GATT到WTO--全球多边贸易体系的发展

建立一个调整世界各国贸易关系的组织 ,以便在比较宽松的环境下开展国际贸易 ,是世界各国的共同愿望。经过战后近半个世纪的艰苦努力 ,从GATT到WTO ,在循序渐进的过程中 ,形成了当今比较完整的国际贸易体系     

浅析新时期我国人口较少民族的扶贫开发对策

改革开放以来,我国人口较少民族在各方面得到了巨大的发展,然而,由于粗放式发展、自然环境、历史等方面的原因,我国人口较少民族少数地区仍至今存在着不同程度的贫困问题,影响了小康社会的全面实现。本文即围绕我国人口较少民族的部分特殊性,以科学发展观为指导,探讨在新的历史时期我国人口较少民族的扶贫开发对策。     

Netzwerken: Reflexionen und Erfahrungen am Beispiel eines TrainerInnen und BeraterInnen-Netzwerkes

How are social networks organized and how much structure and openess do they have? The ambiguity of networking and the grade of organization are discussed and described theoretically and with an authentic example.