On estimating the mean of the selected normal population under the LINEX loss function

Following Parsian and Farsipour (1999), we consider the problem of estimating the mean of the selected normal population, from two normal populations with unknown means and common known variance, under the LINEX loss function. Some admissibility results for a subclass of equivariant estimators are derived and a sufficient condition for the inadmissibility of an arbitrary equivariant estimator is provided. As a consequence, several of the estimators proposed by Parsian and Farsipour (1999) are shown to be inadmissible and better estimators are obtained. Received January 2001/Revised May 2002     

Characterizations of negative multinomial distributions based on conditional distributions

In this paper characterizations of negative multinomial distributions based on conditional distributions have been studied.     

Party alternation,divided government,and fiscal performance within US States

The literature on US state government fiscal performance has examined the role of institutional factors such as budget rules and divided government, but has largely ignored the impact of party alternation. This paper primarily focuses on whether party alternation in the governor’s office affects fiscal performance. Our hypothesis is that frequent party changes create a political environment that impacts fiscal performance. To further assess the impact of party alternation on fiscal performance, we consider our primary hypothesis in conjunction with the degree of division that exists between the governor’s office and the legislature. Using panel data from 37 states between 1971 and 2000 we test the hypothesis that frequent party alternation can be expected to affect fiscal performance and find strong support for the hypothesis. An earlier version of this paper was presented at the 2005 Public Choice Society Meetings. The authors would like to thank the conference participants, William Shughart, Charles Register, Jocelyn Evans, John D. Jackson, Amihai Glazer, and two anonymous referees for their comments. We would also like to thank Craig R. Stiller for his help in the collection of data. Any remaining errors remain the responsibility of the authors.     

Lower Bound Restrictions on Intensities in Data Envelopment Analysis

We propose an extension to the basic DEA models that guarantees that if an intensity is positive then it must be at least as large as a pre-defined lower bound. This requirement adds an integer programming constraint known within Operations Research as a Fixed-Charge (FC) type of constraint. Accordingly, we term the new model DEA_FC. The proposed model lies between the DEA models that allow units to be scaled arbitrarily low, and the Free Disposal Hull model that allows no scaling. We analyze 18 datasets from the literature to demonstrate that sufficiently low intensities—those for which the scaled Decision-Making Unit (DMU) has inputs and outputs that lie below the minimum values observed—are pervasive, and that the new model ensures fairer comparisons without sacrificing the required discriminating power. We explain why the low-intensity phenomenon exists. In sharp contrast to standard DEA models we demonstrate via examples that an inefficient DMU may play a pivotal role in determining the technology. We also propose a goal programming model that determines how deviations from the lower bounds affect efficiency, which we term the trade-off between the deviation gap and the efficiency gap.     

Optimising a Probabilistic Model of the Development of Play in Soccer

We present a probabilistic model based on the one developed by Hernández Mendo and Anguera (Revista de Psicologíca Social, 16(1), 71–93, 2001). Here we have tried to break down the interaction contexts that the opposing teams are able to generate and transform during the game. We are aware that a given player or team does not produce consistent behaviour in similar situations. However, a degree of uncertainty is assumed to exist regarding whether the results obtained are a specific function of the analysis used. In order to carry out this research a category system which optimized that used in the previous model was developed. This system should enable the interaction between teams to be observed within the actual play of a soccer game. A lag sequential analysis was performed on the basis of a coding of the behavioural flow. After describing the behavioural patterns obtained a probabilistic model of the development of play in soccer is proposed.     

Anchor stores

Planned shopping malls usually have one or more department (anchor) stores and multiple specialized retailers selling substitutable commodities in each commodity category. If consumers know their taste for the anchor's commodity and its price, but learn about a retailer's commodity only by costly search, collocation may benefit both store types. Intra-mall competition reduces markups, but anchors guarantee a minimum surplus from search. A mall with many retailers makes finding a suitable specialized commodity highly probable. For some parameters, additional consumer search dominates the loss in retail markups, so a profit-maximizing land developer would rent mall space to both store types.     

Forecasting economic time series using flexible versus fixed specification and linear versus nonlinear econometric models

Nine macroeconomic variables are forecast in a real-time scenario using a variety of flexible specification, fixed specification, linear, and nonlinear econometric models. All models are allowed to evolve through time, and our analysis focuses on model selection and performance. In the context of real-time forecasts, flexible specification models (including linear autoregressive models with exogenous variables and nonlinear artificial neural networks) appear to offer a useful and viable alternative to less flexible fixed specification linear models for a subset of the economic variables which we examine, particularly at forecast horizons greater than 1-step ahead. We speculate that one reason for this result is that the economy is evolving (rather slowly) over time. This feature cannot easily be captured by fixed specification linear models, however, and manifests itself in the form of evolving coefficient estimates. We also provide additional evidence supporting the claim that models which ‘win’ based on one model selection criterion (say a squared error measure) do not necessarily win when an alternative selection criterion is used (say a confusion rate measure), thus highlighting the importance of the particular cost function which is used by forecasters and ‘end-users’ to evaluate their models. A wide variety of different model selection criteria and statistical tests are used to illustrate our findings.     

Developing a tutoring module for presentation of computerized patient management problems

The simulation problem is one of the most commonly used formats in computer-assisted instruction (CAI). In medical education, a patient simulation problem is known as a patient management problem (PMP). A number of computerized PMP systems are currently available. However, to date, there is no record of PMP systems having been developed using artificial intelligence. This is noteworthy since artificial intelligence techniques could help in the generation of more effective and intelligent instructional systems.

This paper analyzes and evaluates existing instructional simulation software in clinical medicine in terms of effective educational design attributes. Components of effective PMP systems thus identified are incorporated into a computerized instructional system which uses artificial intelligence techniques for teaching problem-solving and diagnostic skills to undergraduate medical students.     

A strategic human resource perspective of firm competitive behavior

Embedded within firms are unique stores of intangible human assets that likely influence the way firms compete. We argue that the human and social capital of a firm, particularly at the upper echelon and board of director (BOD) levels, contribute to the firm's awareness of the competitive environment and its motivation and ability to undertake numerous, complex, and forceful competitive actions. We also suggest that the firm's executive compensation systems moderate the effects of these intangible human assets on firm competitive behavior. By examining how human capital, intra-firm social capital, and executive compensation influence firm competitive behavior, we advance a strategic HRM perspective of firm competitive behavior and outline several implications for future research.