The impact of children on a parent's risk of suicide following death of a spouse, Belgium 1991-96

Since Durkheim's work on suicide, the family has widely been seen as providing partial protection against the development of tendencies to suicide. This study assesses the impact of parenthood (both number of children and age of youngest child) on suicide following the death of a spouse. Using data for Belgium in the 5 years following the 1991 census, the study adopts a nested case-control design with information on 3,800 suicides and 75,673 matched controls. The analysis takes into account several social-economic variables. The findings show that the impact of children on the elevated suicide levels found among widows and widowers relative to the still married can be positive or negative, and differs by both age and sex of the parent, age of the child or children, and time since bereavement.     

The International Child Poverty Gap: Does Demography Matter?

According to the Luxembourg Income Study data, the U.S. child poverty rate is the second highest among 15 high-income nations. The present work reveals that 55% of all American children living in a household headed by a single female with no other adult present live in poverty-the highest rate for any of the five living arrangements in the 15 countries examined in this study. While previous analyses have focused on market forces and governmental redistribution across households, we question the contribution of demographic factors that place children in family structures with different poverty risks relative to other factors such as differential market opportunities and governmental benefits for adults caring for children in various living arrangements. Applying a classic demographic decomposition technique to the overall poverty gap, we find that the distributional effect of demographic behavior contributes little to the U.S. poverty gap with other nations (and none with respect to the United Kingdom). Overall differences in labor markets and welfare schemes best explain the U.S. child poverty gap, although for some countries, the gap is accentuated by the gradient of governmental transfers, and for most countries, by the gradient of market earnings across living arrangements.     

Operational challenges in adaptive design implementation

Implementation of adaptive clinical trial designs raises challenges with regard to the processes by which accruing trial data is analyzed, reviewed, and acted upon. In line with current monitoring conventions, it should be viewed that inappropriate knowledge of interim results can raise concerns regarding maintaining trial integrity and interpretability of results. Here we discuss issues related to these processes in adaptive trials, and point out distinctions versus other more familiar monitoring situations. One topic involves the composition of the group of individuals who will have access to interim results in order to recommend adaptations. We discuss operational models for data review by this group; one question addressed is whether in adaptive trials a role in this process for a representative of the study sponsor could at times be warranted, and might be justified if adequate protections are in place. Another issue involves whether adaptations made based upon interim data can convey to observers an amount of information about the results, which could rise to a level of concern. We consider whether different types of adaptations might be more or less problematic with regard to this issue, and recommend steps that might be considered to mitigate this concern.     

On the Assessment of Monte Carlo Error in Simulation-Based Statistical Analyses

Statistical experiments, more commonly referred to as Monte Carlo or simulation studies, are used to study the behavior of statistical methods and measures under controlled situations. Whereas recent computing and methodological advances have permitted increased efficiency in the simulation process, known as variance reduction, such experiments remain limited by their finite nature and hence are subject to uncertainty; when a simulation is run more than once, different results are obtained. However, virtually no emphasis has been placed on reporting the uncertainty, referred to here as Monte Carlo error, associated with simulation results in the published literature, or on justifying the number of replications used. These deserve broader consideration. Here we present a series of simple and practical methods for estimating Monte Carlo error as well as determining the number of replications required to achieve a desired level of accuracy. The issues and methods are demonstrated with two simple examples, one evaluating operating characteristics of the maximum likelihood estimator for the parameters in logistic regression and the other in the context of using the bootstrap to obtain 95% confidence intervals. The results suggest that in many settings, Monte Carlo error may be more substantial than traditionally thought.     

A simple two-stage design for quantitative responses with application to a study in diabetic neuropathic pain

Two-stage designs offer substantial advantages for early phase II studies. The interim analysis following the first stage allows the study to be stopped for futility, or more positively, it might lead to early progression to the trials needed for late phase II and phase III. If the study is to continue to its second stage, then there is an opportunity for a revision of the total sample size. Two-stage designs have been implemented widely in oncology studies in which there is a single treatment arm and patient responses are binary. In this paper the case of two-arm comparative studies in which responses are quantitative is considered. This setting is common in therapeutic areas other than oncology. It will be assumed that observations are normally distributed, but that there is some doubt concerning their standard deviation, motivating the need for sample size review. The work reported has been motivated by a study in diabetic neuropathic pain, and the development of the design for that trial is described in detail.     

在公共服务递送中运营共同生产：服务蓝图的贡献

本文认为,公共服务应从以产品为主导的逻辑转向服务途径。通过采取服务导向,公共服务递送的经验性、组织间和系统性,以及作为共同生产者的服务使用者角色,将一同被考虑。论文将通过服务蓝图的应用,解释共同生产如何操作。并介绍了高等教育中的一个案例。在这一案例中,蓝图的创建将师生汇聚在一起,专注于学生入学的设计,从而改善学生体验,并支持共同生产。      

交通模型网络分配技术

拥挤的城市道路网络的建模工作一直是世界各国研究的课题．各种方法的准确程度也不相同,一个基本的方面就是在追求战略规划目的的同时取得成效,和在准确地表示地域范围内交通运转情况需要之间寻求一种平衡．在许多城市中,需要能够同时评价这两者的灵活的模型．OveArup＆Partners最近已经开发并成功地运用了一个EMME／2模型对奥克兰市、新西兰市做了交通项目估计,同时具体表达了交汇处的延误．这部分的前期工作是由ROHill所承担的,此模型的研究和开发强调了模型中出现的许多重要问题．本文讨论了与拥挤分配模型开发有关的问题,阐述了建立城市范围内的模型的方法．内容包括：a．分配方法;b．稳定性和收敛性;c．城市范围模型的具体水平;d．联系和转弯惩罚函数;e．在没有信号灯的交叉口的延误函数．