Specification Analysis of Diffusion Models for the Italian Short Rate

In recent years, diffusion models for interest rates became very popular. In this paper, we perform a selection of a suitable diffusion model for the Italian short rate. Our data set is given by the yields on 3‐month BOT (Buoni Ordinari del Tesoro), from 1981 to 2001, for a total of 470 observations. We investigate among stochastic volatility models, paying more attention to affine models. Estimating diffusion models via maximum likelihood, which would lead to efficiency, is usually unfeasible because the transition density is not available. Recently, Gallant and Tauchen (1996) proposed a method of moments which gains full efficiency, hence its name of Efficient Method of Moments (EMM); it selects the moments as the scores of an auxiliary model, to be computed via simulation; thus, EMM is suitable to diffusions whose transition density is unknown, but which are convenient to simulate. The auxiliary model is selected among a family of densities which spans the density space. As a by‐product, EMM provides diagnostics that are easy to compute and interpret. We find evidence that one‐factor models and multi‐factor affine models are rejected, while a logarithmic specification of the volatility provides the best fit to the data .     

World Interest Shocks, Capital, and the Current Account

Macroeconomic performance in many developing countries is influenced by international credit conditions. This paper considers a developing economy that faces an upward-sloping supply function of debt. It analyzes how a particular foreign shock, a world interest shock, influences such key macroeconomic variables as output, investment, the current account, and the terms of trade in both short-run and steady-state equilibrium. An intertemporal optimizing model is used to study these issues. This approach permits characterization of the intertemporal adjustment of the indebted economy, and shows that a world interest shock lowers overall economic welfare.     

An Economic Comparison of Production Systems for Sheep

Three production systems for sheep are modeled: spring, winter and accelerated lambing. Actual market price and lamb size over a seven‐year period (1992–98 inclusive) were used to determine which production/marketing system provides the most contribution margin,¹ taking into account costs of production for each system. To determine the cost of production for each system, consensus meetings (a modified Delphi Method) are used to determine costs for 1998 and are then indexed back over the seven years using the Farm Input Price Index. Linear programming² (contribution margin maximizing) computer models are designed. The results indicate that over the seven‐year period, one ewe would show a total contribution margin of $357 in a spring lambing system from a total of 9.80 lambs, $517 in a winter lambing system from 12.25 lambs, and $755 in an accelerated lambing system from 17.64 lambs. Although preference has shifted to larger lambs in the past five years, Christmas and Easter are by far the most important and preferred target markets for any size lamb. Trois systemes de production d'agneaux ont été modelés: agnelage d'automne, agnelage d'hiver et agnelage accéléré. Le prix du marché actuel et la taille des agneaux ont été résuméà travers une période de sept ans (1992–1998 inclusivement). Le prix et la taille ont donc été utilisé pour déterminer quel systéme de production/marketing fournirait la plus grande marge de contribution en ce qui a trait à la taille et le prix des agneaux ainsi que le coût de production. En 1998, plusieurs sessions de discussion ont eu lieu pour en arriver à une opinion commune sur le coût de production pour chaque système. Les prix ont alors été indexe pour les sept années précédentes. On a ensuite conçu des modèles d'optimisation (maximisation de la marge de contribution). Les résultats indiquent qu'il y a une préférence de poids des agneaux associéà des différents périodes au niveau du marché. On a également conclu que certains systèmes d'agnelage sont plus économiques que d'autres dans la production d'agneaux et ce, pour chaque marché.     

让一线管理者成为真正的领导

在那些做得最好的企业里,一线管理人员将60％～70％的时间花在工作现场．其中,有许多时间用在高质量的个人辅导上。这些企业还放权给管理人员,让他们制定决策、相机行事     

Housing tenure and labor market impacts: The search goes on

We develop two search-theoretic models emphasizing firm entry to examine the Oswald hypothesis, the idea that homeownership is linked to inferior labor market outcomes, and compare their predictions to three extant theories. The five models have surprisingly different predictions about the labor market at both the aggregate and micro levels. Using a suitable instrumental variable strategy, we estimate both micro and aggregate level regression models of wages and unemployment and compare the estimates to those predictions. We find that while homeowners are less likely to be unemployed, they also have lower wages, all else equal, compared to renters. In addition, higher regional homeownership rates are associated with a greater probability of individual worker unemployment and higher wages. The outcome of a horserace between our new search-theoretic models is mixed—the wage-posting model predicts observed unemployment impacts while a bargaining variant does a better job explaining observed wages and aggregate labor market outcomes. Overall, we conclude that firm behavior is important for understanding the labor market impacts of homeownership. Because this is the case, regional homeownership rates are not good instruments for individual tenure choice in empirical work. And while individual homeowners may have inferior labor market outcomes as compared to renters, from the viewpoint of society, higher homeownership rates may result in greater job creation and overall production, among other benefits.     

Lessons for Business Ethics from Bioethics

Three widely accepted principles – autonomy, beneficence and justice – provide a useful analytic framework for considering controversies and conflicts in bioethics. Since these principles capture key concepts found in diverse normative theories they provide a starting point from which consistent ethical analysis and comparison can begin. While justice is commonly discussed in the business ethics literature, the other two principles are not widely discussed. This paper investigates whether the principles of autonomy and beneficence provide a framework that is equally useful for framing issues in business ethics. It is argued that they do. First, the principle of autonomy, with its associated notions of informed consent, privacy, confidentiality, voluntariness, self-mastery, and so on, provides a consistent approach to the analysis of diverse issues that arise in business ethics from market research to recruitment practices. Second, it is argued that the relationships between a business and its stakeholders ground duties of beneficence. The principle of beneficence provides a framework for considering the issues that arise in these relationships.     

Web aesthetics effects on perceived online service quality and satisfaction in an e-tail environment: The moderating role of purchase task

This study examines the effects of the two dimensions of web aesthetics, aesthetic formality and aesthetic appeal, on consumers' perceived online service quality and satisfaction during service encounter. The findings showed that, between task-oriented and task-free consumers, the patterns of the effects of the two dimensions of web aesthetics on perceived online service quality and satisfaction are dissimilar. However, regardless of the presence or absence of purchase tasks, aesthetic formality significantly influences perceived online service quality, and aesthetic appeal significantly influences satisfaction. In addition, the effect of aesthetic appeal on satisfaction is negative for task-oriented consumers. Managerial implications on how to manipulate web aesthetics to achieve superior online service quality and high consumer satisfaction are offered.