DS-optimal designs in one way ANOVA

Characterization and construction of optimal designs using the familiar optimality criteria, for example A-, D- and E-optimality are well studied in the literature. However the study of the Distance Optimality (DS-) criterion introduced by Sinha (1970) has very recently drawn attention of researchers. In the present article, we consider the singularly estimable full rank problem of estimating the full set of elementary treatment contrasts using the DS optimality criterion in the set up of a one way ANOVA model. Using a limit argument it turns out that a CRD in which difference between any two allocation numbers is at the most unity is uniquely DS-optimal. Acknowledgement. We are thankful to Prof. B. K. Sinha for suggesting the problem to us and many helpful discussions with him. We are also thankful to the referees for drawing our attention to the reference of Bischoff (1995) and many helpful comments.     

Optimality conditions¶and bubbles in sequential economies¶and bounded relative risk-aversion

We provide specific qualifications in order that Kuhn–Tucker type Euler equations and transversality conditions at infinity hold in stochastic equilibrium models with heterogeneous agents and where assets are traded in sequential markets. It is not assumed that uncertainty is modeled as an event-tree structure or that preferences are necessarily bounded. We also describe an important class of preferences based on bounded relative risk aversion which yields relevant simplifications. Our results are used to establish conditions that rule out asset pricing bubbles. Specific examples of economies with bubbles are also discussed. Received: 28 January 2002 / Accepted: 19 July 2002 We are grateful to the editor and an anonymous referee for their valuable comments. This research was partially supported by MURST (Italy), National Group on “Nonlinear Dynamics and Stochastic Models in Economics and Finance”.     

A play-the-winner-type urn design with reduced variability

We propose a new adaptive allocation rule, the drop-the-loser, that randomizes subjects in the course of a trial comparing treatments with dichotomous outcomes. The rule tends to assign more patients to better treatments with the same limiting proportion as the randomized play-the-winner rule. The new design has significantly less variable allocation proportion than the randomized play-the-winner rule. Decrease in variability translates into a gain in statistical power. For some values of success probabilities the drop-the-loser rule has a double advantage over conventional equal allocation in that it has better power and assigns more subjects to the better treatment. Acknowledgments. I thank Stephen Durham, the associate editor, and the referees for their helpful suggestions.     

Trade intensity,country size and corruption

Abstract. Several authors claim to provide evidence that governmental corruption is less severe in countries where trade intensity is higher or populations are smaller. We argue that theory is highly ambiguous on these questions, and demonstrate that empirical links between corruption and trade intensity – or country size, strongly related to trade intensity – are sensitive to sample selection bias. Most available corruption indicators provide ratings only for those countries in which multinational investors have the greatest interest: these tend to include almost all large nations, but among small nations only those that are well-governed. We find that the relationship between corruption and trade intensity disappears, using newer corruption indicators with substantially increased country coverage. Similarly, the relationship between corruption and country size weakens or disappears using samples less subject to selection bias. Received: July 2001 / accepted: April 2002 We thank Anand Swamy and two anonymous referees for helpful comments and suggestions, Paul Schorosch for able research assistance, and Ray Fisman, Roberta Gatti, Aart Kraay, and Shang-jin Wei for kindly providing data. The conclusions of this paper are not intended to represent the views of the World Bank, its Executive Directors, or the countries they represent.     

Income taxation when markets are incomplete

We investigate the welfare effects of proportional income taxation in a standard general equilibrium model with incomplete markets (GEI). Formally, our analysis is on the allocative effects of state-contingent income tax reforms. Tax reforms are restricted to be anonymous, publicly and truthfully announced before markets open, and they are required to result in an ex-post constrained efficient allocation. Our main result is to show that there do typically exist contingent tax reforms that are Pareto improving. These reforms, acting directly on the asset span, modify private risk-sharing opportunities. Thus, unlike most of the GEI literature, the type of policy transmission mechanism considered does not rely on second-order, relative spot price effects. Yet, the key welfare effects of our tax reforms are substantially equivalent to those induced through changes in relative spot prices, as, for example, in Geanakoplos and Polemarchakis (1986), Geanakoplos et al. (1990), or in Citanna et al. (2001). Mathematics Subject Classification (2000): 58E17, 46N10, 93B29 Journal of Economic Literature Classification: D52, H21, H24, H25     

Consistent estimation in the bilinear multivariate errors-in-variables model

A bilinear multivariate errors-in-variables model is considered. It corresponds to an overdetermined set of linear equations AXB=C, A∈ℝ^m×n, B∈ℝ^p×q, in which the data A, B, C are perturbed by errors. The total least squares estimator is inconsistent in this case.  An adjusted least squares estimator is constructed, which converges to the true value X, as m →∞, q →∞. A small sample modification of the estimator is presented, which is more stable for small m and q and is asymptotically equivalent to the adjusted least squares estimator. The theoretical results are confirmed by a simulation study. Acknowledgements. We thank two anonymous reviewers for their suggestions and corrections.? A. Kukush is supported by a postdoctoral research fellowship of the Belgian office for Scientific, Technical and Cultural Affairs, promoting Scientific and Technical Collaboration with Central and Eastern Europe.? S. Van Huffel is a full professor with the Katholieke Universiteit Leuven.? I. Markovsky is a research assistant with the Katholieke Universiteit Leuven.? This paper presents research results of the Belgian Programme on Interuniversity Poles of Attraction (IUAP V-22), initiated by the Belgian State, Prime Minister's Office – Federal Office for Scientific, Technical and Cultural Affairs of the Concerted Research Action (GOA) projects of the Flemish Government MEFISTO-666 (Mathematical Engineering for Information and Communication Systems Technology), of the IDO/99/03 project (K.U. Leuven) “Predictive computer models for medical classification problems using patient data and expert knowledge”, of the FWO projects G.0078.01, G.0200.00, and G0.0270.02.? The scientific responsibility is assumed by its authors.     

Relative importance of scheduled macroeconomic news for stock market investors

This paper investigates the relative importance of scheduled U.S. macroeconomic news releases for stock valuation. The study focuses on 11 macroeconomic announcements selected on the basis of the previous literature and the Bureau of Labor Statistics classifications of major economic indicators. The paper shows that five out of the 11 announcements have significant influence on stock valuation. These are the Employment Report, NAPM (manufacturing), Producer Price Index, Import and Export Price Indices, and Employment Cost Index. Of these six announcements, the Employment Report and NAPM (manufacturing) exert the greatest influence. The time of the announcement, measured by days from the beginning of the month to the release day, has a moderating impact on the relationship between macroeconomic announcements and its importance.     

The reversal of large stock price declines: The case of large firms

This paper examines the long-run reversal pattern for a sample of large U.S. firms that experienced significant stock price declines of more than 20 percent during a specific month. The results from the analysis are largely consistent with the overreaction hypothesis and significantly greater in magnitude than those reported by previous studies. Six and 12 months after their initial price decline, the stocks of large firms earn approximately 4 and 12 percent in excess of what was expected, respectively. However, the magnitude and trend of that reversal differs substantially across industries. Technology stocks experience the largest and strongest reversal pattern followed by manufacturing stocks, while service industry stocks exhibit a clear downward drift that lasts up to three years and can be described as investorunderreaction to the large price drop.     

In the line of fire: managing expatriates in hostile environments

Abstract

This study explores best practice in the preparation and protection of strategic HRs deployed by Multinational corporations (MNCs) in hostile environments. By building on the literature from the areas of strategic and IHRM, expatriation, as well as risk and crisis management, the limitations and gaps of the extant research are highlighted. This provides a foundation for our investigation through a series of in-depth interviews with corporate executives, and insurers and relocation specialists with professional expertise in protecting and supporting HRs. This represents the first time such a detailed picture of the partnerships between MNCs and the specialists, required to deliver preparation and protection in hostile environments, has been depicted in the IHRM literature. The findings identify the challenges MNCs face when protecting their HRs and highlights the importance of specialist expertise, knowledge, and management. A framework for managing HRs within international hostile environments is subsequently developed offering an opportunity to systematically consider some of the ethical and strategic issues associated with the contemporary challenges of international mobility.