A win ratio approach to comparing continuous non‐normal outcomes in clinical trials

Clinical trials are often designed to compare continuous non‐normal outcomes. The conventional statistical method for such a comparison is a non‐parametric Mann–Whitney test, which provides a P‐value for testing the hypothesis that the distributions of both treatment groups are identical, but does not provide a simple and straightforward estimate of treatment effect. For that, Hodges and Lehmann proposed estimating the shift parameter between two populations and its confidence interval (CI). However, such a shift parameter does not have a straightforward interpretation, and its CI contains zero in some cases when Mann–Whitney test produces a significant result. To overcome the aforementioned problems, we introduce the use of the win ratio for analysing such data. Patients in the new and control treatment are formed into all possible pairs. For each pair, the new treatment patient is labelled a ‘winner’ or a ‘loser’ if it is known who had the more favourable outcome. The win ratio is the total number of winners divided by the total numbers of losers. A 95% CI for the win ratio can be obtained using the bootstrap method. Statistical properties of the win ratio statistic are investigated using two real trial data sets and six simulation studies. Results show that the win ratio method has about the same power as the Mann–Whitney method. We recommend the use of the win ratio method for estimating the treatment effect (and CI) and the Mann–Whitney method for calculating the P‐value for comparing continuous non‐Normal outcomes when the amount of tied pairs is small. Copyright © 2016 John Wiley & Sons, Ltd.     

A visualization method measuring the performance of biomarkers for guiding treatment decisions

Biomarkers that predict efficacy and safety for a given drug therapy become increasingly important for treatment strategy and drug evaluation in personalized medicine. Methodology for appropriately identifying and validating such biomarkers is critically needed, although it is very challenging to develop, especially in trials of terminal diseases with survival endpoints. The marker‐by‐treatment predictiveness curve serves this need by visualizing the treatment effect on survival as a function of biomarker for each treatment. In this article, we propose the weighted predictiveness curve (WPC). Based on the nature of the data, it generates predictiveness curves by utilizing either parametric or nonparametric approaches. Especially for nonparametric predictiveness curves, by incorporating local assessment techniques, it requires minimum model assumptions and provides great flexibility to visualize the marker‐by‐treatment relationship. WPC can be used to compare biomarkers and identify the one with the highest potential impact. Equally important, by simultaneously viewing several treatment‐specific predictiveness curves across the biomarker range, WPC can also guide the biomarker‐based treatment regimens. Simulations representing various scenarios are employed to evaluate the performance of WPC. Application on a well‐known liver cirrhosis trial sheds new light on the data and leads to discovery of novel patterns of treatment biomarker interactions. Copyright © 2015 John Wiley & Sons, Ltd.     

国外教师差别行为的研究现状与展望

近年来国外对教师差别行为的研究取得了较大的成就。文章从差别行为的研究范式、结构与测量及研究内容三个方面对该领域的现状进行描述,并在此基础上对该现象的未来发展趋势进行展望,以期人们能更好地把握该领域的发展轮廓,推动该领域的研究与发展。     

多边贸易体制下中国发展中国家地位问题研究——基于历史、现实与规范的多维考察

当前,发展中国家地位问题受到国际社会的高度关注,已成为世界贸易组织改革中的主要讨论议题。然而,现行世界贸易组织多边规则体系中并没有关于“发展中国家地位”的清晰界定,“自我认定”的方式正遭受一些国家的挑战。发展中国家地位和特殊与差别待遇条款密切相关,世界贸易组织规则体系中涵盖的155项特殊与差别待遇条款为发展中国家的国内政策提供了一定的灵活性,尽管多数为“最佳努力条款”。中国的发展中国家地位兼具身份和契约的双重属性,部分发达国家迫使中国放弃发展中国家地位,本质上旨在继续维持其在国际经济秩序中的主导地位。虽然中国的发展正处于“强起来”的第三阶段,但仍须坚持发展中国家地位不动摇。放弃发展中国家地位并不等于将获得发达国家的自动接纳,相反,还会影响到在其他国际组织和国际事务中的角色扮演,中国的发展离不开广大发展中国家的支持。当然,坚持发展中国家地位并不等于需要和其他发展中成员享受完全一致的差别待遇,在后续谈判中,中国可以保持一定的灵活性。在国际治理中,中国也将继续为国际社会的发展提供解决方案,树立负责任大国形象。     

Double robust estimator in general treatment regimes based on Covariate-balancing

Double robust estimators have double the chance of being a consistent estimator of a causal effect in binary treatments cases. In this paper, we proposed an estimator of a causal effect for general treatment regimes based on covariate-balancing. Under parametrical situation, our estimator has double robustness.     

Predatory purchasing practices in global apparel supply chains and the employment relations squeeze in the Indian garment export industry

While the literature has long acknowledged worker rights abuses in global apparel supply chains, less attention has been paid to the recent worsening of certain decent work deficits and its causes, which this article links to predatory purchasing practices arising from growing power asymmetries. These practices, illustrated here by the garment export industry in India, exert downward pressure on wages and incite non‐standard forms of employment and greater verbal and physical abuse as productivity demands rise. They can be addressed through pricing mechanisms that cover the cost of decent work, appropriate State regulation and worker involvement.     

Participatory shaping of community futures in e‐waste processing hubs: Complexity,conflict and stewarded convergence in a Palestinian context

This article describes an unconventional participatory development approach carried out in an informal e‐waste hub in South‐West Hebron, an area that has collected and processed the bulk of Israeli e‐waste for over a decade. Our approach contributes to the critique and recovery of community representation in participatory development and the search for ways to facilitate representative community engagement. Specifically, we describe our use of a novel Delphi‐like method that allowed us to facilitate a broadly endorsed development trajectory within a heterogeneous and conflicted community. We show how the results yielded by this approach diverged from those that were likely to emerge from more facile forms of participation in ways that are important for other similar e‐waste hubs internationally, which face a destructive status quo on the one hand, or the economically ruinous international policies that ban e‐waste trade from “developed” to “developing” countries on the other. Despite real tensions and cleavages within the affected communities, the process described facilitated a shift from deadlocked environmental versus livelihood positions towards building capacity and regulating existing informal e‐waste trades to preserve livelihoods dependent on these.     

How much is too much: Does the size of income support transfers affect labor supply?

Cash transfer programs pursue mainly protective objectives, but can also impact rural livelihoods by inducing investments in productive activities and changing household labor allocation. We adopt a continuous treatment approach to quantify how households’ labor supply responds to transfer size. We find a shift from paid labor to own farm labor and find that the transfer size is well within a level that would have disincentive effects on time spent on own farm activities. The switch from paid to own farm labor occurs at lower levels of transfers for labor-constrained households, and at higher levels for non-labor constrained households.     

中国教育资源市场化与个体选择：初中课外补习效应异质性探究

本文在中国教育资源市场化的背景下,探究了初中课外补习对学业成绩的效应异质性及其对教育公平的启示。通过分析“中国教育追踪调查”（CEPS）的数据发现,从同质性效应来看,参加课外补习对于提升初中生学习成绩没有显著影响,但参与课外补习的倾向性影响其效应异质性。课外补习有助于提高倾向性处于中间水平学生的学习成绩,表明课外补习受益学生大多来自学习成绩中等的普通工薪家庭。对于倾向性较低的大多数相对弱势的家庭和倾向性较高的少数优势家庭而言,课外补习对学业成绩的作用微乎其微。研究表明,中国教育领域的市场化变革和相关政策的制定需要考虑个体教育选择的复杂性及其对教育公平所造成的深刻影响。