Modelling two types of heterogeneity in the analysis of student success

ABSTRACT

Student dropout is a worldwide problem, leading private and public universities in developed and underdeveloped countries to study the subject carefully or, as has recently been done, to analyse what drives student success. On this matter, different approaches are used to obtain useful information for decision-making. We propose a model that considers the enrolment date to the dropout or graduation date and also covariates to measure student success rates, to identify what the academic and non-academic factors are, and how they drive the student success. Our proposal assumes that there is one part of the population who is not at risk of dropping out, and that the part of the population at risk is heterogeneous, that is, we assume two types of heterogeneity. We highlight two advantages of our model: one is to identify the period of higher risk to dropout due to considering the academic survival time and the second is due to the inclusion of covariates that enable us to identify the characteristics linked to dropout. In this research, we also demonstrate the identifiability of the model and describe the estimation procedures. To exemplify the applicability of the approach, we use two real datasets.     

应用VFP5.0向导开发题库系统软件的方法

利用ＶＦＰ５．０ 向导开发题库系统软件,提出了具体的编程、表单、视图和数据库等设计方法,运行结果表明：该软件具有较好的稳定性。     

Environmentally Responsible Happy Nation Index: Towards an Internationally Acceptable National Success Indicator

Amidst increasing attention to happiness studies by economists, the New Economics Foundation launched in July 2006 the Happy Planet Index (Marks et al. 2006). This is the ratio of the average happy life years (HLY) to the per capita ecological footprint of the country concerned. HLY is in turn the product of the average happiness (or life satisfaction) index and the life expectancy index. Some essential revisions to this index are proposed to reach an internationally acceptable national success indicator that aims positively at long and happy lives but negatively at the external costs of environmental disruption. Hopefully, this ‘environmentally responsible happy nation index’ will lead to some re-orientation of both the market and national governments towards something more fundamentally valuable.

Collective action for the development of national standards for midwifery education in Australia

This article describes a sequence of events that led to the development of national standards for the accreditation of Australian midwifery education programmes for initial registration. This process occurred within a climate of polarised opinions about the value of the introduction of three-year degree programmes for midwives who are not nurses (known as the BMid in Australia) and concerns about the invisibility of midwifery within nursing regulation, education, policy and nomenclature.Concerted efforts to develop standards to inform the introduction of BMid programmes through a process of collective action are described. This involved arguing successfully for the positioning of midwifery as a separate profession from nursing, with a need for its own discreet regulation.     

Probability of success for phase III after exploratory biomarker analysis in phase II

The probability of success or average power describes the potential of a future trial by weighting the power with a probability distribution of the treatment effect. The treatment effect estimate from a previous trial can be used to define such a distribution. During the development of targeted therapies, it is common practice to look for predictive biomarkers. The consequence is that the trial population for phase III is often selected on the basis of the most extreme result from phase II biomarker subgroup analyses. In such a case, there is a tendency to overestimate the treatment effect. We investigate whether the overestimation of the treatment effect estimate from phase II is transformed into a positive bias for the probability of success for phase III. We simulate a phase II/III development program for targeted therapies. This simulation allows to investigate selection probabilities and allows to compare the estimated with the true probability of success. We consider the estimated probability of success with and without subgroup selection. Depending on the true treatment effects, there is a negative bias without selection because of the weighting by the phase II distribution. In comparison, selection increases the estimated probability of success. Thus, selection does not lead to a bias in probability of success if underestimation due to the phase II distribution and overestimation due to selection cancel each other out. We recommend to perform similar simulations in practice to get the necessary information about the risk and chances associated with such subgroup selection designs.     

Mortality–fertility synergies during the demographic transition in the developed world

The classic theory used to explain the demographic transition assumes that mortality is the key explanatory variable influencing the decline in fertility. However, the empirical results obtained in what is known as the Princeton European Fertility Project have led many specialists to question this assumption. Using both national and provincial aggregated data for 25 countries over a long time span, the analysis reported in this paper found that mortality does indeed play a fundamental role in accounting for the main demographic changes that occurred both before and during the transitional period. Others’ research based on individual data has shown clearly that the number of surviving children was indeed an important factor for reproductive decisions. My analysis, using aggregated data, reached largely similar conclusions regarding the role of mortality in changing reproductive trends, via its impact on nuptiality and marital fertility at different stages of the demographic transition.     

Learning and Bayesian updating in long cycle made-to-order (MTO) production

We model production planning for made-to-order (MTO) manufacturing by choosing production rate to minimize expected discounted cost incurred up to a promised delivery date. Products that are MTO are often unique and customized. The associated learning curve slope and other production parameters cannot be precisely estimated before production starts. In this paper, a dynamic and adaptive approach to estimate the effects of learning and to optimize next period production is developed. This approach offers a closed-loop solution through stochastic dynamic programming. Monthly production data are used to update the joint probability distributions of production parameters via Bayesian methods. Our approach is illustrated using historical earned-value data from the Black Hawk Helicopter Program. Managerial insights are obtained and discussed.     

论实现素质教育的困扰及其舒解的取向——从素质教育到成功素质教育

基础教育阶段的“出口导向”是“升学”,素质教育的推行不取决于人们良好的愿望和政府倡导,更与我国优质教育资源的供应及配置方式的改善相关,这是一个长期的渐进的过程。高等教育阶段的“出口导向”是“就业”,当大学毕业生供大于求时,用人单位将由重视“文凭”向更重视大学生“性价比”转变,从而必然导致高等教育阶段更重视学生的素质教育,而其中尤以培养学生在人才市场竞争力为导向的“成功素质教育”理念更有价值。     

大学生科研训练与成功素质教育

加强大学生的科研训练是成功素质教育的重要内容。成功素质教育强调课堂教学与课外活动的结合,专业素质教育与非专业素质教育的结合,以培养学生的创新思维和创造能力,其最佳方式之一就是组织学生开展科研活动,对学生进行必要的且有效的科研训练。     

情商与成才

近几年,大学毕业生就业形势越来越严峻,除了高校扩招因素外,用人单位对大学生群体现状的不满意也是重要原因之一。如何提高情商,把自己锤炼成为受社会欢迎的人才,是当代大学生值得深思的问题。