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.     

An empirical investigation of monetary effects on private consumption expenditures in Austria

This paper presents an econometric investigation of monetary effects on private consumption expenditures in Austria. It tries to add the empirical aspect to the theoretical problem of the relationship between monetary and real sector of an economy.Patinkins theory of the real balance effect provides the link between theoretical and empirical aspects. Taking into consideration further assumptions on aggregation, dynamics and problems of definition of variables, consumption functions of different aggregation levels are specified. Including effects of interest rates and credits one arrives at a first assessment of monetary effects on private consumption expenditures as found from single equation estimates. Significant credit and wealth effects are obtained. Later, systems of equations are estimated and used to investigate real—monetary sector interaction. They allow also a dynamic analysis.In presenting the sequence of microeconomic foundations, further assumptions and macroeconomic functions and systems built upon, it is thought to clarify the connection to traditional theory of real—monetary sectors relationship. It might also give an idea about the resulting problems for meaningful empirical research in this area.

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Zusammenfassung Diese Arbeit beschäftigt sich mit der ökonometrischen Untersuchung monetärer Effekte auf private Konsumausgaben in Österreich. Es wird damit versucht, dem theoretischen Problem der Beziehungen zwischen monetärem und realem Sektor der Wirtschaft einen empirischen Aspekt, der die österreichischen Verhältnisse betrifft, zur Seite zu stellen. Das Bindeglied zwischen Theorie und Empirie stelltPatinkins Theorie des Realkasseneffektes dar, die unter Zuhilfenahme weiterer Annahmen über Aggregation, Definitionen und Dynamik zur Spezifikation von aggregierten und disaggregierten Konsumfunktionen führt. Ergänzt durch Zins- und Krediteffekte läßt sich an Hand von Einzelgleichungen eine erste Einschätzung monetärer Wirkungen auf den privaten Konsum und seine Komponenten durchführen. Es können signifikante Kredit- und Vermögenseffekte festgestellt werden. In diesem Zusammenhang wird auch die Hypothese überprüft, ob die Grenzneigungen zum Konsum aus dem verfügbaren Realeinkommen und aus dem Realfinanzvermögen gleich sind, wie dies durch die Annahme eines kurzfristigen Planungshorizontes impliziert wird.Um die Interaktion von realem und monetärem Sektor zu analysieren, wird ein Gleichungs-system formuliert und geschätzt. Daraus lassen sich Unterschiede zu Einzelgleichungsergebnissen aufzeigen. Mittels alternativer Spezifikation der Konsumgleichungen und der Gleichung des monetären Sektors können Vermögens-, Kredit- und Zinseffekte auch im dynamischen Zusammenhang untersucht werden.Die Aufeinanderfolge von mikroökonomischen Grundlagen, weiterer Annahmen, makroökonomischen Funktionen und schließlich Systemen, soll den Zusammenhang zur traditionellen Theorie der Beziehungen zwischen Geld- und Realsektor verdeutlichen und auf die daraus entstehenden Probleme für eine adäquate empirische Untersuchung hinweisen.

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A preliminary version of this paper was presented at the Winter Meeting of the Econometric Society at Sindelfingen (January 9–11, 1978). It constitutes a condensed version of a project on Money and Private Consumption conducted at the Institute of Econometrics, TU—Vienna, under Prof.G. Tintner. The author is indebted to Prof. Tintner for helpful comments and to Dipl. Ing.R. Rieder for assisting in the computations and providing computer programs. The project was supported financially by the Jubiläusmfonds of the Austrian National Bank.     

Interpretive structural modeling—A useful tool for technology assessment?

Interpretive Structural Modeling (ISM) is a computer based technique for helping small groups develop graphical representations of complex systems. In this paper, the rationale for the use of Interpretative Structural Modeling in activities such as technology assessment is developed and the basic concepts underlying the technique are explored. Several applications of ISM are described and from these experiences some observations are made about the nature and effectiveness of the ISM process and product. ISM was found to provide its users with a systematic and comprehensive method for integrating group judgments in the development of “first-cut‘ structural models. At the same time, however, the technique was found to be relatively inflexible and may, in some instances, inhibit group processes. Possible directions for the development of less rigid methods are suggested.     

Some characteristics of adopters of a major innovation in the computer field and its potential use in marketing

The computer industry is changing dramatically thanks to new technologies that facilitate departure from the lock-in strategies pursued by the long-term industry leaders. New, highly competent competitors have entered the market with the resulting lower profit margins. Innovations in hardware and software are continuously introduced, and a rapid, successful introduction in the market is essential to gain a foothold before new contenders erode the opportunity. The selection of the most likely buyers is therefore important to direct the marketing efforts optimally. An international and a regional field study were carried out to identify the profile of organizations and individuals most likely to adopt an innovation in the computer field. These findings coupled with data base marketing techniques seem promising for a higher success rate in reaching the early adopters (lead users), making it possible to establish a first-mover advantage. The suggested approach can be used in other industries in rapid change.     

Traumberuf oder Verlegenheitslösung?

So far relatively little is known about the situation of Ph.D. students in media and communication research. The main purpose of this study is, therefore, to shed light on the employment and working conditions for young scholars on their way to their doctoral degrees. We conducted a survey of 281 Ph.D. students in Germany, Switzerland and Austria. The results show that, on the one hand, young scholars are intrinsically highly motivated to do their jobs. On the other hand, they perceive an academic career as a very uncertain venture with many obstacles. Furthermore, several types of Ph.D. students can be distinguished: idealists, careerists and waverers. It is shown that only the idealists conform to the concept of a productive and interested scholar. The results are discussed in terms of their importance for the future development of the field.     

Robert W. McChesney: Rich Media, Poor Democracy: Communication Politics in Dubious Times

Ohne Zusammenfassung     

Zur Qualität der Medienkontrolle: Ergebnisse einer Befragung deutscher Rundfunk- und Medienräte

This article presents the results of a survey among German media supervisors (members of supervising boards in public broadcasting stations and state media institutions). Given the increasing commercialization and internationalization of television, the supervising boards play a crucial part in assessing the quality of programs. From among 940 German supervisors, 364 took part in the survey, which covered the individual role conceptions of respondents as well as their attitudes towards quality criteria for television. Results suggest that both the supervisors’ amount of television use and the types of programs they prefer is clearly different from patterns in the population. This, along with the observation that supervisors often criticize what they saw privately, suggests (given the diversity of programs) that too much might be expected of them. Media supervisors do heed quality criteria in their work, but these probably do not correspond to other groups’ criteria, and especially not to the general population’s. To conclude, suggestions are discussed to improve the system of supervising programs by important social groups.