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.     

Nonlinear dynamics in economic modelling

Decisions in Economics and Finance -     

The influence of managers' awareness of climate change,perceived climate risk exposure and risk tolerance on the adoption of corporate responses to climate change

Uncertainties posed by climate change limit companies' ability to understand implications of global warming on business and society at large, hampering the adoption of tangible organizational responses to climate change. Understanding climate action thus requires to investigate influential factors of decision-making under uncertainty, which implies acknowledging managerial interpretations and perceptions about climate issues. Drawing insights from the literature on climate inaction and from corporate sustainability literature, the present study examines awareness of climate change and perceived exposure to climate risks as antecedents of corporate responses to climate change, drawing on a survey of managers of Italian manufacturing companies. In addition, the study tests the moderation of risk tolerance on the relation between perceived climate risk exposure and climate action, suggesting that risk attitudes are a significant factor of decision-making under climate uncertainty. The results support the hypothesis of the model and thus provide several contributions to the literature on business and climate change. Managerial implications and avenues for future research are also discussed.     

Some general results for moments in bivariate distributions

The purpose of this paper is to present a closed formula to compute the moments of a general function from the knowledge of its bivariate survival function. The result is derived by utilizing an integration by parts formula for two variables, which is not readily available in the literature. Many of the existing results are obtained as special cases. Finally, two examples are presented to illustrate the results. In both the examples, mixed moments as well as moments for the series system and parallel system are obtained. The integration by parts formula in two variables, derived here, is of interest in its own right and we hope that it will be useful in other investigations. The integration by parts formula in two variables is derived as a special case of a general formula in n variables.     

Balancing Conflicts of Interest when Employing Spouses

Employees can be put in situations where they are required to make decisions on behalf of the organization as part of their job duties. In these situations, organizations desire that employees make these decisions in the organization’s best interest. In an attempt to ensure that decisions are made in the best interest of the organization, some organizations implement anti-nepotism policies and no spouse rules. While the intent is to minimize conflicts of interest among employees, these policies exact costs to organizations. The present paper examines the costs and benefits of these types of policies, as well as the effects of family-friendly benefits, on organizations. The examination is further laid out in terms of four examples of how these policies and rules can be reframed into conflict of interest policies, allowing organizations to fully experience the benefits of increasing the size of the labor pool by being able to consider spouses and family members as potential applicants, while minimizing conflicts of interest. Finally, recommendations concerning the use of focused conflict of interest policies are made.