The Multilevel Approach to Repeated Measures for Complete and Incomplete Data

Repeated measurements often are analyzed by multivariate analysis of variance (MANOVA). An alternative approach is provided by multilevel analysis, also called the hierarchical linear model (HLM), which makes use of random coefficient models. This paper is a tutorial which indicates that the HLM can be specified in many different ways, corresponding to different sets of assumptions about the covariance matrix of the repeated measurements. The possible assumptions range from the very restrictive compound symmetry model to the unrestricted multivariate model. Thus, the HLM can be used to steer a useful middle road between the two traditional methods for analyzing repeated measurements. Another important advantage of the multilevel approach to analyzing repeated measures is the fact that it can be easily used also if the data are incomplete. Thus it provides a way to achieve a fully multivariate analysis of repeated measures with incomplete data. This revised version was published online in June 2006 with corrections to the Cover Date.     

Sampling equilibrium, with an application to strategic voting

We suggest an equilibrium concept for a strategic model with a large number of players in which each player observes the actions of only a small number of the other players. The concept fits well situations in which each player treats his sample as a prediction of the distribution of actions in the entire population, and responds optimally to this prediction. We apply the concept to a strategic voting model and investigate the conditions under which a centrist candidate can win the popular vote although his strength in the population is smaller than the strengths of the right and left candidates.     

Auditor conservatism and voluntary disclosure: Evidence from the Year 2000 systems issue

This study further examines the phenomenon of conservative auditor behaviour by considering the level of voluntary disclosure of Year 2000 remediation information in company annual reports. Previous studies have provided evidence of conservative auditor behaviour by examining the link between Big 6 auditor choice and accruals (Francis and Krishnan 1999; Becker et al ., 1998; Defond and Subramanyam 1998). Protecting their reputation capital increases Big 6 auditor incentives to act conservatively to avoid litigation risk. We propose and find that Big 6 auditor clients disclose more Year 2000 remediation information than non–Big 6 auditor clients.     

Food Safety Through Food Irradiation: Should it be Adopted More by the EU?

Food Safety Through Food Irradiation: Should it be Adopted More by the EU? Food Irradiation is a food safety technology that can eliminate disease‐causing germs from foods. Faut il encourager ?irradiation pour améliorer la sécurité des aliments en Europe? ?irradiation des aliments est une technique de sécurité alimentaire, qui permet ?en éliminer les germes pathogènes. De même que la pasteurisation du lait, le traitement par des radiations ionisantes permet de tuer les bactéries susceptibles de causer des infections ?origine alimentaire. Celles‐ci sont toujours présentes, et ont de graves conséquences tant pour la santé que pour ?économie. Aux Etats‐Unis, ?irradiation est une technique autorisée pour beaucoup de produits alimentaires. Dans ce pays, le nombre de restaurants et de supermarchés vendant des produits irradiés a augmenté de façon considérable au cours des trois dernières années. Des expérimentations économiques montrent que les consommateurs américains sont disposés à dépenser pour le b?uf irradié des sommes sensiblement supérieures aux suppléments de coûts associés à?irradiation. En Europe, ?utilisation de ?irradiation comme technique de conservation des aliments, susceptible de s'insérer dans des programmes de sécurité alimentaire rigoureux, est beaucoup plus limitée. Jusqu'ici, laliste des produits dont ?irradiation est autorisée dans ?ensemble de la Communauté Européenne ne contient qu'une seule catégorie de produits alimentaires:les herbes aromatiques, épices, et assaisonnements ?origine végétale. Avec la globalisation des circuits commerciaux et le renforcement, exigé par les agences de régulation, des normes de sécurité du champ à la fourchette, la généralisation de l0'irradiation des produits alimentaires devrait profiter à?ensemble des producteurs et des consommateurs européens. Nahrungsmittelsicherheit durch Bestrahlung von Nahrungsmitteln: Sollte dies in der EU verstärkt angewandt werden? Bei der Bestrahlung von Nahrungsmitteln handelt es sich um ein Verfahren zur Gewährleistung der Nahrungsmittelsicherheit, bei der krankheitsverursachende Keime in den Nahrungsmitteln abgetötet werden. Wie bei der Pasteurisierung von Milch können Bakterien mit Hilfe von ionisierenden Strahlen in Nahrungsmitteln abgetötet werden, die anderenfalls durch Nahrungsmittel übertragbare Erkrankungen hervorrufen würden. Diese Erkrankungen stellen eine permanente Bedrohung dar und Ziehen ernstzunehmende Konsequenzen für Gesundheit und Wirtschaft nach sich. In den USA dürfen verschiedene Nahrungsmittelarten bestrahlt werden. In den vergangenen drei Jahren hat die Anzahl der Supermärkte und Restaurants in den USA, die strahlungsbehandelte Produkte anbieten, enorm zugenommen. Erste ökonomische Versuche in den USA legen es nahe, dass die Bereitschaft der Verbraucher, einen höheren Preis für bestrahltes Rinderhackfleisch zu zahlen, sehr viel höher ist als die mit der Bestrahlung verbundenen zusätzlichen Kosten. Die Anwendung der Bestrahlung von Nahrungsmitteln als Werkzeug zur Gewährleistung der Nahrungsmittelsicherheit, welches die strengenNahrungsmittelsicherheitspro‐gramme ergänzen könnte, ist in Europa eher begrenzt. Bislang handelt es sich bei den Produkten, die für die Bestrahlung innerhalb der gesamten EU zugelassen sind, nur um eine einzige Nahrungsmittelklasse: getrocknete aromatische Kräuter und Gewürze. Durch die zunehmende Nachfrage der Aufsichtsbehörden nach Nahrungsmittelsicherheit ?vom Stall bis zum Teller? und die Globalisierung des Nahrungsmittelhandels könnten die Produzenten und Verbraucher in der EU von einer verstärkten Anwendung der Bestrahlung von Nahrungsmitteln profitieren. Like pasteurization of milk, treating food with ionizing radiation can kill bacteria that would otherwise cause foodborne disease. Foodborne illnesses are ever present and have serious health and economic consequences. In the US, food irradiation is approved for use in various foods. The number of supermarkets and restaurants in the US that offer irradiated products has increased dramatically in the last three years. Preliminary economic experiments in the US suggest that consumer willingness to pay for irradiated ground beef is substantially greater than the additional costs associated with irradiation. The use of food irradiation as a food safety tool that could complement rigorous food safety programmes is rather limited in Europe. So far, the list of products authorized for irradiation within the whole EU contains only a single food category: dried aromatic herbs, spices, and vegetable seasonings. With increasing demand by regulatory authorities on food safety from ‘farm to fork’ and the globalization of food trade, EU producers and consumers may benefit from wider adoption of irradiation of food products.     

Organizational slack and firm performance during economic transitions: two studies from an emerging economy. Justin Tan and Mike W. Peng. Strategic Management Journal 24(13) 2003, 1249–1263

The original article to which this erratum refers was published in Strategic Management Journal 24 (13): 1249–1263 (2003).     

An Analysis of Differences in Earnings Between Small and Large Commercial Banks

This paper introduces a simple, yet rich, measure of efficiency changes based on the revenue-generating-ability (RGA) principle. Using this principle, we explain the connections between efficiency changes and the variables, such as pretax profits, interest expense, non-interest expense, profit margins, loan loss provision, and asset quality. These connections are used to explain earnings differences between small and large commercial banks.     

Copyright Damages and Statistics

This paper discusses the statistical issues that arise in conducting an economic damages analysis in the context of a litigation matter involving copyrights. Calculating damages in copyright cases turns out to be a natural application for econometric modelling methods. Surprisingly, elementary statistical issues can be a source of significant debate between the experts in such matters. In this paper, we present a case study and illustrate how issues such as interpretation of p -values and what "rejection of the null hypothesis" really "means" in such matters.