Statistical testing strategies for assessing treatment efficacy and marker accuracy in phase III trials

When a candidate predictive marker is available, but evidence on its predictive ability is not sufficiently reliable, all‐comers trials with marker stratification are frequently conducted. We propose a framework for planning and evaluating prospective testing strategies in confirmatory, phase III marker‐stratified clinical trials based on a natural assumption on heterogeneity of treatment effects across marker‐defined subpopulations, where weak rather than strong control is permitted for multiple population tests. For phase III marker‐stratified trials, it is expected that treatment efficacy is established in a particular patient population, possibly in a marker‐defined subpopulation, and that the marker accuracy is assessed when the marker is used to restrict the indication or labelling of the treatment to a marker‐based subpopulation, ie, assessment of the clinical validity of the marker. In this paper, we develop statistical testing strategies based on criteria that are explicitly designated to the marker assessment, including those examining treatment effects in marker‐negative patients. As existing and developed statistical testing strategies can assert treatment efficacy for either the overall patient population or the marker‐positive subpopulation, we also develop criteria for evaluating the operating characteristics of the statistical testing strategies based on the probabilities of asserting treatment efficacy across marker subpopulations. Numerical evaluations to compare the statistical testing strategies based on the developed criteria are provided.     

Teaching technologies for immigrant children: an exploratory study of elementary school teachers in Russia*

ABSTRACT

Educational institutions are an important setting where psychological, pedagogical, sociocultural, and language adaptation of immigrant children occurs. A number of teaching strategies, practices, approaches, and methods have been described in the literature. In the Russian context, such strategies have been called ‘technologies’. The purpose of the present exploratory study was to describe teaching technologies used by teachers in Russia when working with immigrant students in elementary schools. Responses of forty-five elementary school teachers to open-ended questions describing technologies they use when teaching children with migration backgrounds were analyzed using content analysis. Findings suggest that Russian elementary school teachers used ethno-cultural group, communicative technologies, games, individualized instruction, and differentiated teaching. Many approaches mentioned can be used inclusively with groups of immigrant and non-immigrant students. Importantly, while teachers supplemented classroom instruction with additional Russian language lessons, none mentioned specific techniques for teaching Russian as a non-native language. These findings are discussed in relation to teaching strategies described in the international literature focused on migrant students. Finally, implications for further research are discussed.     

Price bias and common practice in option pricing

Generally, the semiclosed-form option pricing formula for complex financial models depends on unobservable factors such as stochastic volatility and jump intensity. A popular practice is to use an estimate of these latent factors to compute the option price. However, in many situations this plug-and-play approximation does not yield the appropriate price. This article examines this bias and quantifies its impacts. We decompose the bias into terms that are related to the bias on the unobservable factors and to the precision of their point estimators. The approximated price is found to be highly biased when only the history of the stock price is used to recover the latent states. This bias is corrected when option prices are added to the sample used to recover the states' best estimate. We also show numerically that such a bias is propagated on calibrated parameters, leading to erroneous values. The Canadian Journal of Statistics 48: 8–35; 2020 © 2019 Statistical Society of Canada     

不同冷链服务模式下生鲜农产品供应链决策

基于单物流服务商、单供应商和单零售商构成的生鲜农产品供应链，构建3种冷链服务模式：承诺模式、提前要求模式与延后要求模式，探讨不同冷链服务模式对定价与冷链服务水平、企业绩效的影响。研究发现：某种冷链服务模式是否有利于消减数量与质量损耗依赖于产品易腐性、冷链服务成本及其分担比例。供应链成员无法在承诺模式与提前要求模式下形成统一的模式偏好。当物流服务商承担的冷链服务成本比例较低时，相比于提前要求模式，供应商偏好承诺模式，否则，偏好提前要求模式。承诺模式比提前要求模式更有利于物流服务商，然而对于零售商，结果正好相反。数值实验表明，虽然供应链成员无法对冷链服务模式形成整体的一致性偏好，但仍可实现局部的一致性偏好。     

The impact of social power and influence on the implementation of innovation strategies: A case study of a UK mega infrastructure construction project

Influence plays a key role in reaching consensus among multiple actors involved in project-based decision-making processes. While prior literature devotes considerable attention to describing influence, little attention has been paid to influence at the individual level of the strategic project manager within the context of megaprojects. This research intended to fill this knowledge gap by identifying and describing the influence strategies that a strategic project manager applies when implementing innovation strategies on megaprojects. A qualitative case study was used to examine the complex social processes involved in a major UK capital investment programme. The findings underline a critical subset of influence strategies, notably higher-management support, inspirational appeal and bargaining. The study proposes a utilitarian structure of social power comprising selective, supportive and executory power bases.     

Challenges to Connecting Sociology and Service Learning

Service-learning programs are not free from challenges brought about by lack of financial support, lack of widespread commitment from professors, community agencies, and recipients of service, and lack of knowledge and insight in students directly involved in such programs. While service-learning initiatives and programs serve positive functions for organizations and individuals, rhetorical accolades for service learning can distort or omit the realities of program implementation and sustained delivery. This paper specifically explores the following challenges connected to service-learning programs: (1) pedagogical difficulties; (2) student limitations; (3) time constraints; and (4) community cooperation.     

韩国大企业集团的海外扩张战略

自 70年代以来 ,韩国政府通过采取出口导向战略扶持大企业进军海外市场 ,带动了韩国经济的发展。韩国在短短的几十年里由一个农业国变成了一个新兴的工业化国家 ,经济总量居亚洲第三。在韩国经济快速发展中 ,大企业的强力出口、大举投资的海外扩张战略功不可没     

体裁分析在商务语篇教学中的作用

文章介绍了近年来在美国、澳大利亚等国盛行的“体裁教学法”,评价了体裁和体裁分析理论,阐述了体裁分析的发展与特色,探讨了体裁分析法在商务语篇教学中的作用。     

CRM的理念与实施中关键因素分析

随着市场环境、竞争环境的快速变化 ,企业的管理理念、服务观念开始发生重大转变 ,使得CRM(CustomerRelationshipManagement,客户关系管理 )成为当前热点。本文试从CRM在国内外的应用情况、CRM体现的管理理念、服务宗旨以及实施中应考虑的一些重要因素进行分析     

非英语专业学生英语学习策略使用频率的研究

本调查以内蒙古工业大学非英语专业二年级的109名学生为样本,采取观察和问卷形式,考察非英语专业学生使用何种学习策略以及学习策略的使用频率.结果表明六种学习策略中,非英语专业学生最常用的策略是补偿策略,最不常用的策略是记忆策略.最后,作者指出本文的教学实践意义:即学习策略的培训应融于课堂教学中,其应用应体现于课堂教学活动中