Mokken scale analysis for polychotomous items: theory,a computer program and an empirical application

This paper contains three subjects. First, an extension of Mokken's nonparametric item response models from dichotomous items to items with two or more ordered answer categories is proposed. Second, a computer program to analyze multicategory item scores is presented. This program is called MSP. The analyses by means of MSP are based on the multicategory extension of Mokken's theory. Finally, an application of MSP to empirical multicategory test data is presented in order to illuminate its possibilities.     

Unfair dismissal legislation and property rights: some reflections

Starting from the premise that workers have ‘property rights’ in their jobs, this article considers ways in which British unfair dismissal legislation might be said to uphold such rights. The evidence indicates that remedies of compensation and re-employment afford minimal property rights to unfairly dismissed workers.     

THE JOINT ARRIVAL AND DEPARTURE PROCESS FOR THE M/M/l QUEUE

We consider the M/M/1-queue and derive an explicit expression for the joint distribution of the number of arrivals and the number of departures in [0, t), given the number of customers initially present. The derivation is almost purely combinatorial, it avoids the use of generating functions, and immediately yields a simple probabilistic interpretation of the result.     

Urban Regulations and the Price of Land and Housing in Korea

South Korea is a remarkable macroeconomic success story, but it has performed relatively poorly in one respect: the provision of high quality housing at reasonable prices. This paper analyzes the Korean housing market and the market for related inputs, with special emphasis on the regulatory environment.     

Testing equality of variances in the analysis of repeated measurements

The problem of comparing the precisions of two instruments using repeated measurements can be cast as an extension of the Pitman-Morgan problem of testing equality of variances of a bivariate normal distribution. Hawkins (1981) decomposes the hypothesis of equal variances in this model into two subhypotheses for which simple tests exist. For the overall hypothesis he proposes to combine the tests of the subhypotheses using Fisher's method and empirically compares the component tests and their combination with the likelihood ratio test. In this paper an attempt is made to resolve some discrepancies and puzzling conclusions in Hawkins's study and to propose simple modifications.
The new tests are compared to the tests discussed by Hawkins and to each other both in terms of the finite sample power (estimated by Monte Carlo simulation) and theoretically in terms of asymptotic relative efficiencies.     

The ARCO decision: Inroads into the per se rule under Section 1 of the Sherman Act

In this study, the author analyzes the 1990 U.S. Supreme Court decision inAtlantic Richfield Company vs. USA Petroleum Company approving Atlantic Richfield’s maximum pricing plan improsed on its distributors (despite the Court’s recognition that theper se rule forbade such schemes). Theper se rule had been one of the last substantial measures of effective antitrust policy administered by enforcement authorities and the courts, perhaps even more fundamental than scrutiny of proposed mergers and predatory practices. That principle has been weakened by the ARCO decision. The author addresses some of the likely consequences of the ascendancy of the Chicago School and the NeoClassical theory generally in antitrust interpretation.     

Government wage differentials

This paper shows that public sector wages usually exceed private but the size and composition of the differentials depend on sex and level of government. Using a technique derived from the literature on sex discrimination, these differentials are decomposed into a portion attributable to differences in productivity between the two types of workers and a portion ascribed to economic rent. This rent results from public workers' relatively greater political influence in the government wage-setting process and a systematic upward bias in public wages imparted by present government pay policy.     

MSE-improvement of the least squares estimator by dropping variables

It is well known that dropping variables in regression analysis decreases the variance of the least squares (LS) estimator of the remaining parameters. However, after elimination estimates of these parameters are biased, if the full model is correct. In his recent paper, Boscher (1991) showed that the LS-estimator in the special case of a mean shift model (cf. Cook and Weisberg, 1982) which assumes no “outliers” can be considered in the framework of a linear regression model where some variables are deleted. He derived conditions under which this estimator outperforms the LS-estimator of the full model in terms of the mean squared error (MSE)-matrix criterion. We demonstrate that this approach can be extended to the general set-up of dropping variables. Necessary and sufficient conditions for the MSE-matrix superiority of the LS-estimator in the reduced model over that in the full model are derived. We also provide a uniformly most powerful F-statistic for testing the MSE-improvement.