Robust inference from multiple test statistics via permutations: a better alternative to the single test statistic approach for randomized trials

Formal inference in randomized clinical trials is based on controlling the type I error rate associated with a single pre‐specified statistic. The deficiency of using just one method of analysis is that it depends on assumptions that may not be met. For robust inference, we propose pre‐specifying multiple test statistics and relying on the minimum p‐value for testing the null hypothesis of no treatment effect. The null hypothesis associated with the various test statistics is that the treatment groups are indistinguishable. The critical value for hypothesis testing comes from permutation distributions. Rejection of the null hypothesis when the smallest p‐value is less than the critical value controls the type I error rate at its designated value. Even if one of the candidate test statistics has low power, the adverse effect on the power of the minimum p‐value statistic is not much. Its use is illustrated with examples. We conclude that it is better to rely on the minimum p‐value rather than a single statistic particularly when that single statistic is the logrank test, because of the cost and complexity of many survival trials. Copyright © 2013 John Wiley & Sons, Ltd.     

Spatial approaches to social work – theoretical foundations and implications for practice and research

ABSTRACT

Spatial approaches have inspired and grounded the social sciences and social geography already for a longer time. Beyond these models, the theory discourse on social work developed innovative concepts and models of socio-spatial approaches. They set a special focus on aspects of individual and social development, the concept of acquirement and emancipatory approaches to spatial design. For interventions, special methods for socio-spatial analyses were developed. This article reflects the main approaches of this theory discourse and asks for its key implications for social work practice and research.     

Discursive strategies for internal legitimacy: Narrating the alternative organizational form

A significant body of academic work has explored the ways in which hybrid organizations seek to secure external legitimacy. However, there is a more limited understanding of the ways in which organizational units in hybrid organizations seek to acquire internal legitimacy – legitimacy which is conferred by internal stakeholders. This study draws on more than a century of communications in a Dutch cooperative bank to uncover how a major organizational unit enacted distinct discursive strategies to seek internal legitimacy. The paper extends prior work by showing how internal legitimacy work – the efforts to shape, reinforce, or suppress internal legitimacy judgments – in a hybrid organization is a dynamic process whereby an internal unit generates multiple complementary narratives to promote a fit between its own attributes and the legitimacy evaluations by internal audiences. In addition, it shows how internal legitimacy work can promote this fit by attempting to manipulate not only the impressions of the internal unit's attributes, but also its audiences’ understanding of wider cultural norms of the day, on which their legitimacy judgments are based. In this vein, the paper highlights how discursive internal legitimacy work seeks to generate a taken-for-granted organizational position for the internal units concerned.     

The EPA Health Risk Assessment of Methylcyclopentadienyl Manganese Tricarbonyl (MMT)

This paper describes the U.S. Environmental Protection Agency's assessment of potential health risks associated with the possible widespread use of a manganese (Mn)-based fuel additive, methylcyclopentadienyl manganese tricarbonyl (MMT). This assessment was significant in several respects and may be instructive in identifying certain methodological issues of general relevance to risk assessment. A major feature of the inhalation health risk assessment was the derivation of Mn inhalation reference concentration (RfC) estimates using various statistical approaches, including benchmark dose and Bayesian analyses. The exposure assessment component used data from the Particle Total Exposure Assessment Methodology (PTEAM) study and other sources to estimate personal exposure levels of particulate Mn attributable to the permitted use of MMT in leaded gasoline in Riverside, CA, at the time of the PTEAM study; on this basis it was then possible to predict a distribution of possible future exposure levels associated with the use of MMT in all unleaded gasoline. Qualitative as well as quantitative aspects of the risk characterization are summarized, along with inherent uncertainties due to data limitations.     

试论现代人的社会化

通过社会学的观点从现代人社会化的理论含义、现代人社会化的基本特征和现代人社会化的基本内容等三个方面,对现代人经过社会化科学地适应社会生活,在社会生活中健康和谐地成长,成为现代社会所期望的“社会人”作简单的论述。     

我国东西部发展差异的主成分分析

改革开放以来,我国那种大一统的传统经济模式被打破了.由于政策和区位的因素,各地采取了不同的发展模式,导致了各地发展速度和规模的差异.主成分分析法可以将多个变量综合成少数几个变量,以此来更好地揭示各种发展模式总体上的差异.     

论彝族“尔比尔吉”的内涵及特征

彝族"尔比尔吉"是生产与生活经验知识的结晶,其内涵丰富,独具特色,与凉山历史文化相辅而行,反映了凉山彝族自然地理和各个民族经济、政治、历史、文化以及人民心理素质、语言风格等各方面的特点,成为广义的、独特的、典型的凉山彝族文化特征,具有不可替代的研究价值和保留价值。     

广西新闻教育办学模式的发展创新及新闻教育前景展望

当前广西的新闻教育遇到了良好的发展契机,如何抓住有利时机,不断创新发展是广西新闻院系面临的普遍问题。对此,本文认为新闻院校要培养出适应广西经济社会发展和传媒发展的新闻类人才,就应该在办学模式上有所创新与发展。本文从办学模式的概念入手,对当前广西新闻院系的办学模式以及存在的问题作了分析,在此基础上进一步分析了广西新闻教育在新闻人才培育目标、培育内容、培育方法三个方面该如何实现创新与发展,使培育出的新闻人才适应广西经济社会的发展。     

论宋代僧诗中的偈颂赞

宋代僧诗是宋诗的重要组成部分,而偈颂赞类作品在宋僧诗中占有主要地位,此类作品源于佛经,但又不能等同于佛经中的偈、颂、赞,其主要内容是以文学手段宣扬佛教教义,其中的临终偈颂尤具特色和代表性。语言极为俚俗,形式灵活多变,是偈颂赞类宋僧诗的主要艺术特色。     

Robust regression: an inferential method for determining which independent variables are most important

Consider the usual linear regression model consisting of two or more explanatory variables. There are many methods aimed at indicating the relative importance of the explanatory variables. But in general these methods do not address a fundamental issue: when all of the explanatory variables are included in the model, how strong is the empirical evidence that the first explanatory variable is more or less important than the second explanatory variable? How strong is the empirical evidence that the first two explanatory variables are more important than the third explanatory variable? The paper suggests a robust method for dealing with these issues. The proposed technique is based on a particular version of explanatory power used in conjunction with a modification of the basic percentile method.