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.     

Ratings and confirmation

We present a formalism which makes explicit and precise the confirming effect of multiple observers and repeated trials on composite ratings, considering the relevant subjective inputs.     

RECENT DEVELOPMENTS IN THE THEORY OF NATURAL MONOPOLY

Abstract. This paper examines two important recent developments in the theory of natural monopoly, or more generally the theory of market structure. The first is a series of papers, involving Baumol with various co-authors, investigating the theory of industry structure, whilst the second is particularly associated with the names of Shaked and Sutton, and the relationship they develop between product differentiation and industry structure. The paper surveys and to some extent contrasts these two new approaches.
Baumol et al. 's contribution is seen to be in the area of clarifying the concept of natural monopoly, refining the definitions of multiproduct costs, and developing a notion of social efficiency applicable to industries where economies of scale are important. Shaked and Sutton employ a new definition of natural monopoly unrelated to market size and utilize information about consumers'income distributions to develop their notion of vertical product differentiation and natural oligopoly.     

Analysis of arrest rates for trends in criminality

During the 1960s, the United States experienced a substantial increase in crime with the rates of reported crime more than doubling. It has been postulated that the increase in the proportion of young adults in the population which also occurred during the Sixties is a primary factor in the increase in crime. In this paper, we attempt to explore this question by partitioning the recent increases in rates between an increasing crime-committing propensity for various demographic groups on one hand, and a changing demographic mix to the other. We do this by analyzing arrest rates by demographic group over time. However, since arrest rates are a complex function of both criminality and police activity, a model is developed which attempts to distinguish between these phenomena. The model is estimated using data on age, race, and sex-specific arrest rates for Pittsburgh residents over the period 1967–1972. The results of the analysis suggest that there has been no significant increase in criminality for men in the Pittsburgh population, while there is some evidence of increased criminality for women. However, this increase may reflect an increased willingness of the police to arrest women. We hesitate to generalize our conclusions too widely from the experience of a single urban center. Additional analysis, using the model developed here, of arrest rates from other cities or regions would do much to illuminate this very significant issue.     

Dynamic effects of externalities,optimal saving and economic growth

Conclusion Recognizing the fact that provision of mixed public goods can result in both consumption externalities of the Samuelsonian variety as well as production externalities we set out to extend the earlier results of Rao and Kalpagam (1977) on the effect of public goods on economic growth. In so doing, we considered three standard specifications of production externalities and enlarged the concept of consumption displacement. Our basic conclusion is that the results of our earlier paper remain valid under the more general conditions set out in this paper.     

Implicit social preferences in the Norwegian system of indirect taxation

The revelation of implicit social preferences is a fresh field of econometrics. In this paper the theoretical setting is a model of optimal indirect taxation. A parametric preference function is specified, which makes it possible to separate and quantify three different effects. First, it provides a condensed quantitative measure of the degree of income inequality aversion. Second, a set of parameters evaluate external social costs induced by the consumption of certain commodities. Finally, the function allows estimation of implicit equivalent income scales. The authors consider the results as a source of information about an important part of Norwegian tax policy.