Estimation of a non-invertible moving average process: The case of overdifferencing

The effect of differencing all of the variables in a properly specified regression equation is examined. Excessive use of the difference transformation induces a non-invertible moving average (MA) process in the disturbances of the transformed regression. Monte Carlo techniques are used to examine the effects of overdifferencing on the efficiency of regression parameter estimates, inferences based on these estimates, and tests for overdifferenccing based on the estimator of the MA parameter for the disturbances of the differences regression. Overall, the problem of overdifferencing is not serious if careful attention is paid to the properties of the disturbances of regression equations.     

Effect of outliers on the estimation of parameters

Summary The estimation of parameter in the type of distributionf(x)=b x ^{–1 /b} exp (–x ^b (/b),x>0, is considered, when several outliers of the type , ,r=1,2, ...,k, are present in the data. The estimates of as well as of 's are put in the closed form. Special cases, Weibull, Gamma and Exponential are considered for the case of single outlier. Actual estimates are calculated from the generated samples of size 2 and 3 for the Weibull and Exponential.     

A brief study of age specific birth proportions,Japan and Singapore

The suitability of age-specific birth proportions (ASBP), or percentage distribution of births, as a rough and ready index of fertility change was analyzed by establishing a theoretical framework for its limitations and uses. The discussion suggested that the utility of ASBP as an indicator of fertility change depends on the characteristics and behavior of the population being considered. The concept was then empirically applied to birth trends in Japan and Singapore for 2 different time periods. Analysis suggested that ASBP trends in Japan reflected changes in age-specific fertility rates relative to general fertility rate as well as trends in parity distribution. The Singapore analysis was more complicated, raising different issues. As very limited empirical work has been done on ASBPs, the utility of ASBPs as an indicator of fertility change cannot be definitely ascertained. It was suggested however that ASBP trends may be applicable in countries where the age distribution of fertile-aged women is fairly stable. More empirical research should be done on ASBP trends in other countries, the behavior of A matrix as discussed in this paper, and useful empirical relationship of ASBP with other fertility measures.     

Do norms of decision-making styles,organizational design and management affect performance of Japanese firms? an exploratory study of medium and large firms

The success and resilience of Japanese firms have led many scholars and practitioners to theorize and speculate about the impact of what they have termed the 'Japanese management style' upon performance. There have been few studies that have attempted to explore empirically the links between the way Japanese firms organize, manage and decide, and their performance. This paper investigates the association between norms of decision-making style, organizational design and management, and some measures of firm performance. The empirical pattern of norms was assessed on the basis of responses of a random sample (N = 349) of Japanese managers. The study demonstrates that while there appears to be no support for the proposition that certain norms universally affect performance, in some sectors the impacts of norms on decision-making style, organizational design and management may be significant. The study concludes with the implications for theory building of this empirical exploration.     

Public Schools and In-migration in North Carolina Counties, 1975–80

Abstract . The migration model presented in this paper indicates (hat the academic quality of public schools, independent of their racial composition, is an important determinant of in-migration in North Carolina counties. The failure to control for school quality is shown to lead to a significant overestimate of the negative impact of school racial mix. These results accord with the Tiebout Hypothesis and with a growing body of other research which suggests that the distributions of public services and other amenities are the principal determinants of recent migration patterns in the U.S.     

Political Profit: Taxing and Spending in the Hierarchical State

A bstract . The actions of government fall into two types: taxes (the taking of property ) and expenditures (the awarding of gifts ). Politicians profit as long as the value of resources raised from taxation exceeds the cost of expenditures. From their point of view, fiscal efficiency consists in maximizing the support obtained by spending and minimizing the opposition generated by taxing. This is accomplished by spending on well-organized groups and taxing the uninformed public. This results in the "iron law of political redistribution" in which income and wealth are transferred from the latter to the former. In a hierarchical State , it is usually profitable for those at the top to centralize control over taxing and spending, if for no other reason than to make it difficult for politicians at lower levels to compete against them. This gives rise to the "law of hierarchical centralization "—in a hierarchical State, power becomes centralized over time. The greater the power of government, the faster this process takes place. In order to avoid this problem, one could design constitutions which are non-hierarchical in nature, in which each unit of government is completely autonomous from the others, as firms are in a free market.     

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.