Late entry,market shares and competitive survival: The case of synthetic fibers

This paper examines product policy in relation to the experience curve and product life cycle concepts in the context of the experience of the thirteen major firms in the Western European synthetic fibers industry. It examines the hypothesis based on Boston Consulting Group and the Profit Impact of Market Share (PIMS) evidence that late entrants to a market will be at a competitive disadvantage because they lack the accumulated experience of the pioneering firms. For each of the three main synthetic fibres, acrylic, nylon and polyester, it was found that the early entrants who established major market shares early in the growth phase of the product life cycle were able to maintain that leadership nearly twenty years later. In contrast not only did almost all the late entrants fail to achieve significant market shares but in the difficult market conditions between 1974 and 1981 they provided seven out of nine market withdrawals.     

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.     

Unionism and the public sector

It is incorrect and misleading to speak of unionization as a ‘human right’. The only human right is ‘self-ownership’, i.e. to pursue goals with one's own abilities but with no force or fraud against others. Government cannot dispense rights, only privileges and protections to some at the expense of others. A minimal degree of coercion exercised by government is unavoidable. But labor unions are not governments. Government has granted significant privileges to unions in the private sector, but such are not appropriate for public sector unions.     

The entropies: Some roots of ambiguity

Entropy concepts have developed in four general contexts—thermodynamics, communication theory, statistical information theory and social and life sciences. These concepts have five distinct mathematical forms. Ambiguity and complexity in utilization of the concept has been heightened by this multi-faceted heritage. Effective utilization may be strengthened by a sharper articulation of entropy through combinations of literal, mathematical and graphical modes of expression. Geography and planning as user disciplines have important responsibilities in enhancing cross-disciplinary communication of this important adisciplinary concept. Implications of these arguments for the social sciences include the need for caution in drawing social analogies from the ambiguous entropy concepts of statistical mechanics; and an indication of the potential benefits of social science models based on the unambiguous entropic constructs of statistical information theory.     

Robustness to the unavailability of data in block designs

We present general results for finding or boundingt _maxB , the maximum number of arbitrary whole blocks of observations which can be removed from a block design, and still leave all of the elementary treatment contrasts estimable. The block sizes may be larger than the number of treatments. The results are applied to BBDs, reinforced BIBDs and BBDs, BTIBDs, and a series of variance balanced incomplete block designs with two block sizes. Also given for most of these designs, are results fort _max, the maximum number of arbitrary, scattered observations that can become unavailable, and still leave all of the elementary treatment contrasts estimable.The work was undertaken while Dr. Whittinghill was visiting Ohio State University, and supported by a grant from the Natural Sciences Division, Colby College, Waterville, Maine.     

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.