Unbiased estimation of expected return using CAPM

Estimation of expected return is required for many financial decisions. For example, an estimate for cost of capital is required for capital budgeting and cost of equity estimates are needed for performance evaluation based on measures such as EVA. Estimates for expected return are often based on the Capital Asset Pricing Model (CAPM), which states that expected excess return (expected return minus the risk-free rate) is equal to the asset's sensitivity to the world market portfolio (β) times the risk premium on the “world market portfolio” (the market risk premium). Since the world market portfolio, by definition, contains all assets in the world, it is not observable. As a result, an estimate for expected return is commonly obtained by taking an estimate for β based on some index (as a proxy for the world market portfolio) and an estimate for the market risk premium based on a potentially different index and multiplying them together. In this paper, it is shown that this results in a biased estimate for expected return. This is undesirable since biased estimates lead to misallocation of funds and biased performance measures. It is also shown in this paper that the straightforward procedure suggested by Fama and MacBeth [J. Financ. Econ. 1 (1974) 43] results in an unbiased estimate for expected return. Further from the analysis done, it follows that, for an unbiased estimate, it does not matter what proxy is used, as long as it is used correctly an unbiased estimate for expected return results.     

零售企业敏捷供应链系统CSS-SCM的研究

供应链核心在于实现供应链环节中的信息沟通，数据互换和协同工作，改造和整合企业的业务流程，因此供应链系统模型应该具有动态可重构的特点，系统主体的构成也应反映这种思想，在系统中引入“大规模定制”，“工作流”的新思想和“异构系统兼容”，“通用报表”以及“三层架构应用体系及开发手段”等新技术将使供应链系统更为“敏捷”。     

石化企业乙烯物料平衡的实例分析

乙烯物料平衡是石化企业的主要物料平衡之一，由于乙烯衍生物的装置较多，影响石化企业乙烯物料平衡的因素也多。在分析了S企业的四个实例后，可以看出，搞好乙烯的物料平衡工作，可以提高乙烯下游装置的开工率和负荷率，从而提高企业的经济效益。     

供应链管理绩效评价及激励机制

本文通过分析供应链管理的特点、目标和内容，提出供应链管理绩效评价指标体系，其中矩阵指标具有一定的创新，且较好地反映了供应链企业之间的复杂关系。介绍了确定供应链管理的绩效指标值的两种方法，并分析了供应链管理六种激励模式。     

Robustness issues in multilevel regression analysis

A multilevel problem concerns a population with a hierarchical structure. A sample from such a population can be described as a multistage sample. First, a sample of higher level units is drawn (e.g. schools or organizations), and next a sample of the sub‐units from the available units (e.g. pupils in schools or employees in organizations). In such samples, the individual observations are in general not completely independent. Multilevel analysis software accounts for this dependence and in recent years these programs have been widely accepted. Two problems that occur in the practice of multilevel modeling will be discussed. The first problem is the choice of the sample sizes at the different levels. What are sufficient sample sizes for accurate estimation? The second problem is the normality assumption of the level‐2 error distribution. When one wants to conduct tests of significance, the errors need to be normally distributed. What happens when this is not the case? In this paper, simulation studies are used to answer both questions. With respect to the first question, the results show that a small sample size at level two (meaning a sample of 50 or less) leads to biased estimates of the second‐level standard errors. The answer to the second question is that only the standard errors for the random effects at the second level are highly inaccurate if the distributional assumptions concerning the level‐2 errors are not fulfilled. Robust standard errors turn out to be more reliable than the asymptotic standard errors based on maximum likelihood.     

矿渣微粉和磨细粉煤灰双掺混凝土的试验与应用

讨论了矿渣微粉和磨细粉煤灰双掺(简称FS双掺)在大体积混凝土以及高强混凝土中的试验与应用,以此体现了它们在经济上的显著效应。     

搞好《建筑工程概预算》课程教学的思考

根据《建筑工程概预算》课程的特点,结合教学实践经验,对如何搞好该课程的教学做了一些思考：强调课程重要性,使学生明确课程学习的意义;精心挑选教材,备足教学参考资料;注重培养学生分析、解决问题的能力和自学能力;开展课程设计教学,提高教学质量;充分发挥教师的主导作用,培养“双师型”的教师;教学中理论联系实际,支持、鼓励学生参加执业资格证考试。     

市场调查中的不完全事后分层估计量

在使用多个分类变量对样本进行交叉事后分层时，经常面临边缘总值已知、格子总值未知的不完全事后分层问题。针对这一情况，给出两种估计量即搜索比率估计量和广义搜索比率估计量。     

中国政府统计抽样调查制度的总体框架研究

随着中国市场经济体制的逐步确立,政府的职能在逐渐转变,政府对统计数据的要求也在变化,这就要求政府统计调查制度也随之改革。适应市场经济体制和中国政府管理的特点以及城乡统筹发展的要求,政府统计调查应该以抽样调查为主体,抽样调查队伍和机构应主要设立在地市一级,调查的指标体系和内容应该改革与调整,企业抽样调查应该采用名单框和区域框结合的双框抽样方式。对于抽样调查得到的数据资料,不仅应当汇总得出各种可用于宏观经济管理与分析的总量指标数据和分类数据,而且还应当建立起全部被调查企业和被调查家庭的数据库,供政府部门和国内的科学研究机构进行微观社会经济活动主体层次的研究。     

理性的限度——素质教育漫谈之三

素质教育的任务之一是要引导民众从过于执著的感性追求的迷雾中走出来,在提高 理性观照层面的同时,也能够意识到理性的残缺之所在,并形成一种自我弥补的内在动力。在普 遍失落的理性当中,值得注意的是工具理性对认知理性的屏蔽,群体理性对个体理性的排斥,造 成理性的悬置和知与行的分离,并最终导致理性力量的丧失。因此,通过学与思,提升个体的认 知理性,由此而提升群体理性的层次,将成为当前素质教育的第一要义