Retesting symmetry and homogeneity in a cointegrated demand system with bootstrapping: The case of meat demand in Greece

A small Almost Ideal Demand System is estimated for Greek meat consumption using the Johansen procedure in conjunction with parametric bootstrapping and Bartlett corrections. Asymptotic Wald and likelihood ratio tests broadly support the predicted number of cointegrating relationships but reject symmetry and homogeneity. Bootstrapping and Bartlett corrections give support to symmetry and homogeneity but give less support for the predicted number of cointegrating relationships.Jel classification: C32 D12First version received: September 2001/Final version received: March 2003     

Accounting measures and international pricing models: Justifying accounting homogeneity

We study the importance of homogeneous accounting data when testing international versions of asset pricing models. Specifically, we focus on a pricing model commonly used by practitioners – the Fama–French three-factor model – which uses accounting information and has traditionally performed poorly at the cross-country level. We show that international versions of the model perform significantly better if the accounting information is homogeneous across firms. We apply the model to a set of firms that follow common accounting standards – the IAS/IFRS – and also to firms that have issued ADRs in the US – and therefore must report following both US GAAP and their own domestic standards. In both cases our results show that the accounting dimension is relevant: the use of homogeneous accounting measures allows for much higher goodness-of-fit of international versions of the three-factor model, at levels similar to those of domestic versions and superior to those of non-homogeneous versions. This suggests that further accounting homogeneity could lead to more accurate pricing and valuation of international assets and to an improvement of the efficiency of international fund allocation.     

高职院校物流专业建设存在的问题及对策

随着物流的发展,很多高职院校纷纷开设了物流专业,但高职院校在物流专业建设的过程中存在着如专业设置同质化严重、实训实习条件不足等一系列的问题,为了培养符合社会发展需要的物流应用型人才,是高职院校亟待解决的问题之一.文章在分析我周高职院校物流专业建设现状的基础上,总结了我国目前离职院校物流专业建设存在的问题,并对如何解决存在的问题,提出了相应的对策.     

收入效用差异的心理动因及其数学分析

本文就收入效用存在的差异,分析其形成的心理动因,并建立相应的数学模型给予解释。     

Retirement and Social Security in a Probabilistic Voting Model

Why are social security transfers associated with retirement rules? This paper focuses on the political interactions between retirement and social security. Using a probabilistic voting approach, it analyzes why old people are induced to retire in order to receive pension transfers from the young. A crucial hypothesis is that leisure in old age represents a “merit good,” which is positively valued by all agents in the society, young and old. Thus, the politicians choose to tax the labor income of the old, to induce them to retire. Retirement increases the level of ideological homogeneity of the old. In fact, once retired, the elderly are more “single-minded,” since they only care about redistributive issues, such as pensions. This increase in their political power allows them to win the political game and to receive a positive transfer from the young (social security).     

Consumption processes and positively homogeneous projection properties

We constructively prove the existence of time-discrete consumption processes for stochastic money accounts that fulfill a pre-specified positively homogeneous projection property (PHPP) and let the account always be positive and exactly zero at the end. One possible example is consumption rates forming a martingale under the above restrictions. For finite spaces, it is shown that any strictly positive consumption strategy with restrictions as above possesses at least one corresponding PHPP and could be constructed from it. We also consider numeric examples under time-discrete and -continuous account processes, cases with infinite time horizons, and applications to income drawdown and bonus theory.      

原料药产品均一性验证中统计方法的使用

探讨了原料药均一性验证中统计方法的使用问题,通过对比3种常用的数理统计方法的使用条件和精度及对具体例子进行计算,指出了3种方法各自的优缺点,提出一般情况下应使用假设检验,但也可根据实际情况进行调整。     

Composite outcome measurement in clinical research: the triumph of illusion over reality?

Abstract

Composite measures that combine different types of indicators are widely used in medical research; to evaluate health systems, as outcomes in clinical trials and patient-reported outcome measurement. The potential advantages of such indices are clear. They are used to summarise complex data and to overcome the problem of evaluating new interventions when the most important outcome is rare or likely to occur far in the future. However, many scientists question the value of composite measures, primarily due to inadequate development methodology, lack of transparency or the likelihood of producing misleading results. It is argued that the real problems with composite measurement are related to their failure to take account of measurement theory and the absence of coherent theoretical models that justify the addition of the individual indicators that are combined into the composite index. All outcome measures must be unidimensional if they are to provide meaningful data. They should also have dimensional homogeneity. Ideally, a specification equation should be developed that can predict accurately how organisations or individuals will score on an index, based on their scores on the individual indicators that make up the measure. The article concludes that composite measures should not be used as they fail to apply measurement theory and, consequently, produce invalid and misleading scores.     

Are cryptocurrencies homogeneous?

This article investigates if cryptocurrencies returns' are similarly affected by a selection of demand- and supply-side determinants. Homogeneity among cryptocurrencies is tested via a least absolute shrinkage and selection operator (LASSO) model where determinants of Bitcoin returns are applied to a sample of 12 cryptocurrencies. The analysis goes beyond existing research by simultaneously covering different periods and design choices of cryptocurrencies. The results show that cryptocurrencies are heterogeneous, apart from some similarities in the impact of technical determinants and cybercrime. The cryptocurrency market displays evidence of substitution effects, and design choices related explain the impact of the determinants of return.