Some properties of the length of the shortest half

This paper discusses some properties of the length of the shortest half proposed by Rousseeuw and Leroy (1988) as a robust scale estimator.     

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.     

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.     

BOOK REVIEWS AND NOTES

Book reviews in this article: G.D.H. COLE AND INDUSTRIAL DEMOCRACY: A REVIEW: The World of Labour Introduction by John Lovell G.D.H. COLE AND INDUSTRIAL DEMOCRACY: A REVIEW: Self-Government in Industry Introduction by J. G. Corina G.D.H. COLE AND INDUSTRIAL DEMOCRACY: A REVIEW: Workshop Organisation Introduction by A. I. Marsh WORKPLACE INDUSTRIAL RELATIONS: Building: Teamwork or Conflict? by L. G. Bayley The Management of Wage Payment Systems by Alan Gillespie Labour Relations on the Docks by M. Jackson ORGANIZATIONAL BEHAVIOUR: Social Psychology of the Work Organisation by A. S. Tannenbaum Organisational Problems in European Manufacture by T. D. Weinshall LABOUR ECONOMICS: Manpower Economics by E. B. Jakubaus and Neil A. Palomba Labour Economics by J. E. King Unemployment and Wage Inflation with Special Reference to Britain and the U.S.A. by J. Taylor UNEMPLOYMENT: Regional Unemployment Differences in Great Britain by P. C. Cheshire Interregional Migration Models and their Application to Great Britain by R. Weeden The Changing Pattern of Employment—Regional Specialisation and Industrial Localisation in Britain by M. Chisholm and J. Oeppen Men Out of Work—A Study of Unemployment in Three English Towns by M. J. Hill, R. M. Harrison, A. V. Sargeant and V. Talbot Do The Poor Want To Work? A Social-Psychological Study of Work Orientation by L. Goodwin Marienthal: The Sociography of an Unemployed Community by M. Jahoda, P. F. Lazarsfeld and H. Zeisel b     

A reconciliation of recent results in optimal taxation theory

The recent papers by Guesnerie and Diewert on tax reforms are interpreted as contributions to the characterization of second-best optima. This paper demonstrates that when it is possible to achieve any feasible direction of change in supplies by a differential change in producer prices, there are unique producer support prices. Under these circumstances, the apparent differences between Guesnerie and Diewert are reconciled. Optimality conditions with nonunique support prices are also considered.