Inferences on the Means of Two Log-Normal Distributions: A Computational Approach Test

In this article, we propose a novel approach for testing the equality of two log-normal populations using a computational approach test (CAT) that does not require explicit knowledge of the sampling distribution of the test statistic. Simulation studies demonstrate that the proposed approach can perform hypothesis testing with satisfying actual size even at small sample sizes. Overall, it is superior to other existing methods. Also, a CAT is proposed for testing about reliability of two log-normal populations when the means are the same. Simulations show that the actual size of this new approach is close to nominal level and better than the score test. At the end, the proposed methods are illustrated using two examples.     

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.     

Blinded continuous monitoring in clinical trials with recurrent event endpoints

In studies with recurrent event endpoints, misspecified assumptions of event rates or dispersion can lead to underpowered trials or overexposure of patients. Specification of overdispersion is often a particular problem as it is usually not reported in clinical trial publications. Changing event rates over the years have been described for some diseases, adding to the uncertainty in planning. To mitigate the risks of inadequate sample sizes, internal pilot study designs have been proposed with a preference for blinded sample size reestimation procedures, as they generally do not affect the type I error rate and maintain trial integrity. Blinded sample size reestimation procedures are available for trials with recurrent events as endpoints. However, the variance in the reestimated sample size can be considerable in particular with early sample size reviews. Motivated by a randomized controlled trial in paediatric multiple sclerosis, a rare neurological condition in children, we apply the concept of blinded continuous monitoring of information, which is known to reduce the variance in the resulting sample size. Assuming negative binomial distributions for the counts of recurrent relapses, we derive information criteria and propose blinded continuous monitoring procedures. The operating characteristics of these are assessed in Monte Carlo trial simulations demonstrating favourable properties with regard to type I error rate, power, and stopping time, ie, sample size.     

Modifications of sequential designs in bioequivalence trials

Bioequivalence (BE) studies are designed to show that two formulations of one drug are equivalent and they play an important role in drug development. When in a design stage, it is possible that there is a high degree of uncertainty on variability of the formulations and the actual performance of the test versus reference formulation. Therefore, an interim look may be desirable to stop the study if there is no chance of claiming BE at the end (futility), or claim BE if evidence is sufficient (efficacy), or adjust the sample size. Sequential design approaches specially for BE studies have been proposed previously in publications. We applied modification to the existing methods focusing on simplified multiplicity adjustment and futility stopping. We name our method modified sequential design for BE studies (MSDBE). Simulation results demonstrate comparable performance between MSDBE and the original published methods while MSDBE offers more transparency and better applicability. The R package MSDBE is available at https://sites.google.com/site/modsdbe/ . Copyright © 2015 John Wiley & Sons, Ltd.     

商业银行董事会治理的独立有效性研究

根据经济合作与发展组织、巴塞尔银行监管委员会和中国银行业监督管理委员会等组织关于公司治理的相关原则、指引和法律规定,对商业银行董事会的独立有效性进行了综合分析,得出商业银行董事会的独立有效性主要体现在独立董事的独立性,职能委员会的独立性以及独立董事占董事会成员的比例3个方面以及规范的独立董事、职能委员会的产生机制和明确的独立董事、职能委员会的责权利制度是确保商业银行董事会独立有效性基础的结论,并提出中国商业银行董事会的适度规模为11人,其中独立董事占董事会成员的合适比例为50％以上的建议。     

中国近代公司监事会独立性问题初探

监事会作为公司专门的监督机关，保持与被监督对象的独立性是其监督有效的前提。尽管近代公司在监事会的独立性方面有所规定，但在实践中效果并不理想。究其原因，除了相关规定不完善、股权集中及监事会与董事会职能重叠以外，最根本的原因还在于公司内部的集权体制。公司的集权性质，决定了近代公司监事会难以保持独立性，这对于今天公司制度的建设，具有积极的借鉴意义。     

建立多层次资本市场 促进经济快速发展

目前我国资本市场在规模、功能、结构、规则等方面存在着严重的制度缺陷.资本市场发展与经济发展不协调的现状表明,我国迫切需要培育和建立多层次的资本市场,其主要模式包括主板市场、二板市场、三板市场以及以区域性资本市场为体系的多层次资本市场,扩充资本市场的服务对象,健全和完善资本市场服务体系,以适应我国经济发展过程中不同类型企业的融资需求.     

"民官比"不是影响政治体制改革的重要因素

在政治体制改革中,公务员或国家干部人数的多少并不是一个关键因素,重要的是必须把政府的社会定位(包括角色、权力和责任)划分清楚。与世界各国相比较,我国197.69∶1(或116.27∶1)的“民官比”并不高,因此,今后的政治体制改革不需要再把精力集中在“精简”上,而应按邓小平的部署,首先把党政分开和权力下放的工作做好。毕竟“小政府”是指“政府权力受限制”,而非“人数更少”;“大社会”是指“社会权利更广泛”,而非“人数更多”。     

中小企业信用担保与信用环境建设的研究

市场经济条件下中小企业信用担保机构的运作模式应采用政府组建，市场化运作或混合组建，市场化运作；其组织形式应是事业法人制；其运作规则应为公平、多元、规范、稳健。从担保基金的盈亏上看，决定担保规模的因素实质上是一个地区企业的总体信用状况，创造良好的信用环境将成为中小企业信用担保机构生存和发展的关键之所在。加强法制建设、社会征信机构建设和企业伦理建设是实现这一目标的基本途径。