Measuring Performance Heterogeneity within Groups A Two-Dimensional Approach

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1 TECHNICAL UNIVERSITY BERGAKADEMIE FREIBERG TECHNISCHE UNIVERSITÄT BERGAKADEMIE FREIBERG FACULTY OF ECONOMICS AND BUSINESS ADMINISTRATION FAKULTÄT FÜR WIRTSCHAFTSWISSENSCHAFTEN Michael Fritsch Andreas Stephan Measuring Performance Heterogeneity within Groups A Two-Dimensional Approach F R E I B E R G W O R K I N G P A P E R S F R E I B E R G E R A R B E I T S P A P I E R E #

2 The Faculty of Economics and Business Administration is an institution for teaching and research at the Technische Universität Bergakademie Freiberg (Saxony). For more detailed information about research and educational activities see our homepage in the World Wide Web (WWW): Addresses for correspondence: Prof. Dr. Michael Fritsch Technical University of Freiberg Faculty of Economics and Business Administration Lessingstraße 45, D Freiberg, Germany Phone: ++49 / 3731 / Fax: ++49 / 3731 / michael.fritsch@tu-freiberg.de Prof. Dr. Andreas Stephan German Institute for Economic Research (DIW Berlin) Königin-Luise-Straße 5, D Berlin, Germany Phone: ++49 / 030 / astephan@diw.de ISSN The Freiberg Working Paper is a copyrighted publication. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, translating, or otherwise without prior permission of the publishers. Coordinator: Prof. Dr. Michael Fritsch All rights reserved.

3 I Contents Abstract / Zusammenfassung... II 1. Introduction The performance distribution curve and measurement of aggregate performance A two-dimensional approach for measuring heterogeneity within industries Numerical examples Conclusions...6 References...6

4 II Abstract We introduce a new two-dimensional measure for the heterogeneity of performance within groups of economic units. This measure accounts both, for the relative performance of the single units of groups and their relative size. We demonstrate that the new measure leads to a much more differentiated description of heterogeneity than alternative measures, for example, the mean or range. In particular, we provide an example to demonstrate that the proposed measure of heterogeneity is relatively robust with regard to extreme values of units ( outliers ) with a relatively small size. Keywords: Performance, heterogeneity, dispersion measures JEL classification: C10, C43, L25 Zusammenfassung Wir stellen ein neues zweidimensionales Maß für die Heterogenität der Leistungsfähigkeit innerhalb von Gruppen ökonomischer Einheiten vor. Dieses Maß berücksichtigt neben der Leistungsfähigkeit auch die relative Größe der betreffenden Einheiten. Wir zeigen, dass dieses neue Maß die Heterogenität innerhalb von Gruppen wesentlich differenzierter beschreibt als alternative Maße, wie etwa das arithmetische Mittel und die Spannweite. Anhand eines numerischen Beispiels kann gezeigt werden, dass unser Maß vergleichsweise robust gegenüber extremen Werten ( Ausreißern ) relativ kleiner Einheiten ist. Schlagworte: Leistungsfähigkeit, Heterogenität, Streuungsmaße JEL Klassifikation: C10, C43, L25

5 1 1. Introduction Economic units are typically quite heterogeneous with respect to their economic performance. For example, while some firms operate at the technological frontier and earn high profits, others lag considerably behind and are scarcely able to survive competition. Conventional means of measuring such dispersion of performance, for example, using the range or the standard deviation, disregard the relative importance of the economic units. Furthermore, these traditional measures tend to be rather vulnerable with regard to extreme values. We propose a new measure of heterogeneity of economic units based on a twodimensional approach and taking into account both the relative size of economic units and dispersion of performance. An illustrative example demonstrates the robustness of this measure regarding outliers. 2. The performance distribution curve and measurement of aggregate performance As a fictive example, Figure 1 shows a graphical exposition of a sample of economic units, such as a group of households or the firms of an industry, showing diverging levels of economic performance. 1 Performance may describe different issues, for instance, profit, productivity or efficiency. In this graph, the units are arranged according to their performance in descending order, starting with the best performing unit. This unit constitutes the 100 percent benchmark for measuring the relative performance of the other entities in the respective group; that is, the performance of a unit is measured in relation to the performance of the best performing group member with the value of 100 percent in this distribution. The length of the line for each unit is equivalent to its relative size that may be measured by its share of employment, assets, gross production or turnover in the whole group (Figure 1). Small entities are represented by short lines and larger entities by longer lines. The resulting curve provides an informative portrayal of the distribution of performance within the respective group. The value of about 30 1 This exposition is inspired by diagrams in Salter (1969). Salter displayed productivity levels of firms in ascending order, starting with the least efficient firm.

6 2 percent for the worst performing unit in Figure 1 indicates that its performance level is about 70 percent below that of the performance leader. 2 The total range of the performance distribution is calculated by subtracting the percent value of the least performing group member from 100 percent. Figure 1: The performance distribution curve The distribution of performance levels of individual units points to a basic issue. When taking the unit with the highest value of the performance indicator as a benchmark for assessing the performance of the other group members, this performance level should be somewhat representative of the whole group. Best performing outliers lead to figures of relative performance that may be judged inadequate or wrong. Therefore, measures for the distribution of performance within groups should not give too much weight to extreme values. This implies that the range between the minimum and the maximum value is probably not well suited to this means of measurement. Compared to the range, other conventional 2 In an empirical analysis for German manufacturing industries in the period from 1992 to 2001, we find that the median efficient production unit is about 59 percent of the maximum efficiency level and that the minimum efficiency level is, on average, about 38.5 percent. There are, however, large differences between the various industries with regard to these figures. See Fritsch and Stephan (2003) for details.

7 3 measures of heterogeneity such as the standard deviation and the coefficient of variation have the advantage that they are using the information for all members of the respective group, not only the minimum and maximum. However, these measures do not account for the relative size of the individual units. It makes a huge difference whether the best performing unit has a large share or whether it plays only a marginal role. 3. A two-dimensional approach for measuring heterogeneity within industries Our measure of heterogeneity is based on the performance distribution curve. It is the area between the performance distribution curve and the median value of the performance indicator in the sample. This heterogeneity area (ha) is defined as follows: ha I = 1 p i p m s i, where p i, (0 p i 1), denotes the relative performance level of a unit i (i = 1,, I) as a percentage and p m is the relative performance level of the median unit. This median is defined according to the measure of relative size that is used for constructing the curve. The relative size of a unit as a percentage is denoted by s i (0 s i 1). Our measure can have values between 0 and 0.5. It will be zero if all units have the same performance value and, conversely, it is be 0.5 if half of the group performs at 100% and the other half has a performance of 0%. The measure takes two dimensions into account: the relative performance level as well as the relative size of the units. This two-dimensional character makes it relatively robust with regard to extreme values. In contrast to other measures of heterogeneity such as the standard deviation or the coefficient of variation, our area measure is sensitive to relative size of the group members, for example, whether the high performing units have a relatively large share or constitute only a marginal share of the group. Since performance is expressed as the percent deviation from the highest attained performance level and size is measured as the percent share of the group, this indicator is independent from any absolute figures and the values can be directly compared between groups. The measure is also

8 4 relatively robust with regard to small units with extreme values that may not be considered as being representative for the group. 4. Numerical examples Some numerical examples (Table 1) may demonstrate the properties of our heterogeneity measure. Let us assume that a group consists of ten units (unit I X) with relatively normally distributed performance levels as displayed in column A of Table 1. For the sake of simplicity, we assume that the performance value of the best performing unit is 100 so that absolute and relative performance is identical. Each of the units in column A constitutes 10 % of the group. In columns B to D, these units have the same performance levels as in column A. However, their percent shares vary. Whilst the values of the mean and range are not affected by these differences and remain constant in columns A to D, the median and the heterogeneity area react to the variation of shares within the group. In column B, the best performing unit has a share of 30 %, whilst the rest is equally distributed among the remaining units, which attain about 7.78 % each. Compared to the constellation of column A, diversity within the group has increased because a larger proportion is now performing well above the average. Accordingly, the value of the heterogeneity area is higher. However, as soon as the share of the performance leader is more than 50 %, it represents the median performance level and the area measure of heterogeneity assumes relatively low values. If a relatively large unit is performing at about the average level, the heterogeneity area also tends to be relatively small (see columns C and D). In order to demonstrate the properties of our heterogeneity measure with regard to extreme values, column E shows a constellation in which a further unit (unit XI) is included in the group that is characterized by performance twice as good as the best unit in the old group. Since outliers tend to be quite small, we assume that the additional unit has a share of only 1 %. The other ten units have an equal share of 9.9 % each. The inclusion of an additional case with a higher

9 5 Table 1: Numerical examples of alternative measures of heterogeneity Absolute performance / relative performance / share A B C D E F Unit I 100 / 100 / / 100 / / 100 / / 100 / / 50 / / 100 / 9.9 Unit II 90 / 90 / / 90 / / 90 / / 90 / / 45 / / 90 / 9.9 Unit III 80 / 80 / / 80 / / 80 / / 80 / / 40 / / 80 / 9.9 Unit IV 75 / 75 / / 75 / / 75 / / 75 / / 37.5 / / 75 / 9.9 Unit V 70 / 70 / / 70 / / 70 / / 70 / / 35 / / 70 / 9.9 Unit VI 65 / 65 / / 65 / / 65 / / 65 / / 32.5 / / 65 / 9.9 Unit VII 60 / 60 / / 60 / / 60 / / 60 / / 30 / / 60 / 9.9 Unit IIX 50 / 50 / / 50 / / 50 / / 50 / / 25 / / 50 / 9.9 Unit IX 40 / 40 / / 40 / / 40 / / 40 / / 20 / / 40 / 9.9 Unit X 30 / 30 / / 30 / / 30 / / 30 / / 15 / / 30 / 9.9 Unit XI / 100 / 1 5 / 5 / 1 Mean Median Range Standard deviation Heterogeneity area (ha) Ha Ha performance level has two effects. First, whilst the absolute performance of the incumbents remains constant, the values for their relative performance decrease due to the higher reference level given by the additional unit. They are, therefore, closer together than in the reference constellation shown in column A. However, in contrast to this greater homogeneity among the old units, the inclusion of a unit with better performance also leads to greater dispersion and, consequently, greater heterogeneity within the new group. In the case displayed in column E, our area measure gives greater weight to the first of the two effects, indicating an overall decrease of heterogeneity within the sample. The main reason for this result is the small share of the extreme case (unit XI) which is only 1 %. If this share were larger, the inclusion of this case could result in a rising value of the indicator. The values for the range and for the standard deviation do not account for the relative size of the extreme value and point towards an increase in the heterogeneity level within the sample. Adding a small outlier with relatively low performance (unit XI in column F) to the initial group of ten units (column A) leads to more hetero-

10 6 geneity according to all three measures. The reason why our area measure indicates increasing heterogeneity here is that the additional case does not lead to a change of the reference point for calculating relative performance. However, the increase of the area measure is only 2.7 % compared to an increase in the range of 11.8 % and in the standard deviation of about 4.3 %. This demonstrates the robustness of our measure with regard to small outliers. To obtain a heterogeneity indicator that is even less affected by outliers, the measure may be calculated without including the best and the worst performing units. Table 1 shows the values without the upper and the lower 10 % (ha 10-90) and 25 % (ha 25-75). The difference, often relatively large, between these indicators and the values for the complete heterogeneity area indicates that in many cases the greater part of the heterogeneity is due to the tails of the distribution. 5. Conclusions We have presented a two-dimensional approach to measuring performance heterogeneity within a sample of economic units that accounts for the relative size of these units. This new measure leads to a more precise description of performance heterogeneity and is, in particular, more robust with regard to outliers. 3 References Fritsch, M., Stephan, A., The Distribution of Technical Efficiency within Industries An Empirical Analysis. Paper presented at the 30 th EARIE Conference, August 24-26, Helsinki, Finland. Salter, W.E., Productivity and Technical Change. 2 nd. Ed. Cambridge University Press, Cambridge. 3 For an analysis of technical efficiency within industries on the basis of this measure, see Fritsch and Stephan (2003).

11 List of Working Papers of the Faculty of Economics and Business Administration, Technische Universität Bergakademie Freiberg /1 Michael Nippa, Kerstin Petzold, Ökonomische Erklärungs- und Gestaltungsbeiträge des Realoptionen-Ansatzes, Januar. 00/2 Dieter Jacob, Aktuelle baubetriebliche Themen Sommer 1999, Januar. 00/3 Egon P. Franck, Gegen die Mythen der Hochschulreformdiskussion Wie Selektionsorientierung, Nonprofit- Verfassungen und klassische Professorenbeschäftigungsverhältnisse im amerikanischen Hochschulwesen zusammenpassen, erscheint in: Zeitschrift für Betriebswirtschaft (ZfB), 70. (2000). 00/4 Jan Körnert, Unternehmensgeschichtliche Aspekte der Krisen des Bankhauses Barings 1890 und 1995, in: Zeitschrift für Unternehmensgeschichte, München, 45 (2000), /5 Egon P. Franck, Jens Christian Müller, Die Fußball-Aktie: Zwischen strukturellen Problemen und First-Mover- Vorteilen, Die Bank, Heft 3/2000, /6 Obeng Mireku, Culture and the South African Constitution: An Overview, Februar. 00/7 Gerhard Ring, Stephan Oliver Pfaff, CombiCar: Rechtliche Voraussetzungen und rechtliche Ausgestaltung eines entsprechenden Angebots für private und gewerbliche Nutzer, Februar. 00/8 Michael Nippa, Kerstin Petzold, Jamina Bartusch, Neugestaltung von Entgeltsystemen, Besondere Fragestellungen von Unternehmen in den Neuen Bundesländern Ein Beitrag für die Praxis, Februar. 00/9 Dieter Welz, Non-Disclosure and Wrongful Birth, Avenues of Liability in Medical Malpractice Law, März. 00/10 Jan Körnert, Karl Lohmann, Zinsstrukturbasierte Margenkalkulation, Anwendungen in der Marktzinsmethode und bei der Analyse von Investitionsprojekten, März. 00/11 Michael Fritsch, Christian Schwirten, R&D cooperation between public research institutions - magnitude, motives and spatial dimension, in: Ludwig Schätzl und Javier Revilla Diez (eds.), Technological Change and Regional Development in Europe, Heidelberg/New York 2002: Physica, /12 Diana Grosse, Eine Diskussion der Mitbestimmungsgesetze unter den Aspekten der Effizienz und der Gerechtigkeit, März. 00/13 Michael Fritsch, Interregional differences in R&D activities an empirical investigation, in: European Planning Studies, 8 (2000), /14 Egon Franck, Christian Opitz, Anreizsysteme für Professoren in den USA und in Deutschland Konsequenzen für Reputationsbewirtschaftung, Talentallokation und die Aussagekraft akademischer Signale, in: Zeitschrift Führung + Organisation (zfo), 69 (2000), /15 Egon Franck, Torsten Pudack, Die Ökonomie der Zertifizierung von Managemententscheidungen durch Unternehmensberatungen, April. 00/16 Carola Jungwirth, Inkompatible, aber dennoch verzahnte Märkte: Lichtblicke im angespannten Verhältnis von Organisationswissenschaft und Praxis, Mai. 00/17 Horst Brezinski, Der Stand der wirtschaftlichen Transformation zehn Jahre nach der Wende, in: Georg Brunner (Hrsg.), Politische und ökonomische Transformation in Osteuropa, 3. Aufl., Berlin 2000, /18 Jan Körnert, Die Maximalbelastungstheorie Stützels als Beitrag zur einzelwirtschaftlichen Analyse von Dominoeffekten im Bankensystem, in: Eberhart Ketzel, Stefan Prigge u. Hartmut Schmidt (Hrsg.), Wolfgang Stützel Moderne Konzepte für Finanzmärkte, Beschäftigung und Wirtschaftsverfassung, Verlag J. C. B. Mohr (Paul Siebeck), Tübingen 2001, /19 Cornelia Wolf, Probleme unterschiedlicher Organisationskulturen in organisationalen Subsystemen als mögliche Ursache des Konflikts zwischen Ingenieuren und Marketingexperten, Juli.

12 00/20 Egon Franck, Christian Opitz, Internet-Start-ups Ein neuer Wettbewerber unter den Filteranlagen für Humankapital, erscheint in: Zeitschrift für Betriebswirtschaft (ZfB), 70 (2001). 00/21 Egon Franck, Jens Christian Müller, Zur Fernsehvermarktung von Sportligen: Ökonomische Überlegungen am Beispiel der Fußball-Bundesliga, erscheint in: Arnold Hermanns und Florian Riedmüller (Hrsg.), Management-Handbuch Sportmarketing, München /22 Michael Nippa, Kerstin Petzold, Gestaltungsansätze zur Optimierung der Mitarbeiter-Bindung in der IT- Industrie - eine differenzierende betriebswirtschaftliche Betrachtung -, September. 00/23 Egon Franck, Antje Musil, Qualitätsmanagement für ärztliche Dienstleistungen Vom Fremd- zum Selbstmonitoring, September. 00/24 David B. Audretsch, Michael Fritsch, Growth Regimes over Time and Space, Regional Studies, 36 (2002), /25 Michael Fritsch, Grit Franke, Innovation, Regional Knowledge Spillovers and R&D Cooperation, Oktober. 00/26 Dieter Slaby, Kalkulation von Verrechnungspreisen und Betriebsmittelmieten für mobile Technik als Grundlage innerbetrieblicher Leistungs- und Kostenrechnung im Bergbau und in der Bauindustrie, Oktober. 00/27 Egon Franck, Warum gibt es Stars? Drei Erklärungsansätze und ihre Anwendung auf verschiedene Segmente des Unterhaltungsmarktes, Wirtschaftsdienst Zeitschrift für Wirtschaftspolitik, 81 (2001), /28 Dieter Jacob, Christop Winter, Aktuelle baubetriebliche Themen Winter 1999/2000, Oktober. 00/29 Michael Nippa, Stefan Dirlich, Global Markets for Resources and Energy The 1999 Perspective -, Oktober. 00/30 Birgit Plewka, Management mobiler Gerätetechnik im Bergbau: Gestaltung von Zeitfondsgliederung und Ableitung von Kennziffern der Auslastung und Verfügbarkeit, Oktober. 00/31 Michael Nippa, Jan Hachenberger, Ein informationsökonomisch fundierter Überblick über den Einfluss des Internets auf den Schutz Intellektuellen Eigentums, Oktober. 00/32 Egon Franck, The Other Side of the League Organization Efficiency-Aspects of Basic Organizational Structures in American Pro Team Sports, Oktober. 00/33 Jan Körnert, Cornelia Wolf, Branding on the Internet, Umbrella-Brand and Multiple-Brand Strategies of Internet Banks in Britain and Germany, erschienen in Deutsch: Die Bank, o. Jg. (2000), /34 Andreas Knabe, Karl Lohmann, Ursula Walther, Kryptographie ein Beispiel für die Anwendung mathematischer Grundlagenforschung in den Wirtschaftswissenschaften, November. 00/35 Gunther Wobser, Internetbasierte Kooperation bei der Produktentwicklung, Dezember. 00/36 Margit Enke, Anja Geigenmüller, Aktuelle Tendenzen in der Werbung, Dezember /1 Michael Nippa, Strategic Decision Making: Nothing Else Than Mere Decision Making? Januar. 01/2 Michael Fritsch, Measuring the Quality of Regional Innovation Systems A Knowledge Production Function Approach, International Regional Science Review, 25 (2002), /3 Bruno Schönfelder, Two Lectures on the Legacy of Hayek and the Economics of Transition, Januar. 01/4 Michael Fritsch, R&D-Cooperation and the Efficiency of Regional Innovation Activities, Januar. 01/5 Jana Eberlein, Ursula Walther, Änderungen der Ausschüttungspolitik von Aktiengesellschaften im Lichte der Unternehmenssteuerreform, Betriebswirtschaftliche Forschung und Praxis, 53 (2001), /6 Egon Franck, Christian Opitz, Karriereverläufe von Topmanagern in den USA, Frankreich und Deutschland Elitenbildung und die Filterleistung von Hochschulsystemen, Schmalenbachs Zeitschrift für betriebswirtschaftliche Forschung (zfbf), (2002). 01/7 Margit Enke, Anja Geigenmüller, Entwicklungstendenzen deutscher Unternehmensberatungen, März.

13 01/8 Jan Körnert, The Barings Crises of 1890 and 1995: Causes, Courses, Consequences and the Danger of Domino Effects, Journal of International Financial Markets, Institutions & Money, 13 (2003). 01/9 Michael Nippa, David Finegold, Deriving Economic Policies Using the High-Technology Ecosystems Approach: A Study of the Biotech Sector in the United States and Germany, April. 01/10 Michael Nippa, Kerstin Petzold, Functions and roles of management consulting firms an integrative theoretical framework, April. 01/11 Horst Brezinski, Zum Zusammenhang zwischen Transformation und Einkommensverteilung, Mai. 01/12 Michael Fritsch, Reinhold Grotz, Udo Brixy, Michael Niese, Anne Otto, Gründungen in Deutschland: Datenquellen, Niveau und räumlich-sektorale Struktur, in: Jürgen Schmude und Robert Leiner (Hrsg.), Unternehmensgründungen - Interdisziplinäre Beiträge zum Entrepreneurship Research, Heidelberg 2002: Physica, /13 Jan Körnert, Oliver Gaschler, Die Bankenkrisen in Nordeuropa zu Beginn der 1990er Jahre - Eine Sequenz aus Deregulierung, Krise und Staatseingriff in Norwegen, Schweden und Finnland, Kredit und Kapital, 35, /14 Bruno Schönfelder, The Underworld Revisited: Looting in Transition Countries, Juli. 01/15 Gert Ziener, Die Erdölwirtschaft Russlands: Gegenwärtiger Zustand und Zukunftsaussichten, September. 01/16 Margit Enke, Michael J. Schäfer, Die Bedeutung der Determinante Zeit in Kaufentscheidungsprozessen, September. 01/17 Horst Brezinski, 10 Years of German Unification Success or Failure? September. 01/18 Diana Grosse, Stand und Entwicklungschancen des Innovationspotentials in Sachsen in 2000/2001, September /1 Jan Körnert, Cornelia Wolf, Das Ombudsmannverfahren des Bundesverbandes deutscher Banken im Lichte von Kundenzufriedenheit und Kundenbindung, in: Bank und Markt, Verlag Fritz Knapp, Frankfurt a. M., ISSN , Jg. 31, Heft 6, /2 Michael Nippa, The Economic Reality of the New Economy A Fairytale by Illusionists and Opportunists, Januar. 02/3 Michael B. Hinner, Tessa Rülke, Intercultural Communication in Business Ventures Illustrated by Two Case Studies, Januar. 02/4 Michael Fritsch, Does R&D-Cooperation Behavior Differ between Regions? Industry and Innovation, 10 (2003), /5 Michael Fritsch, How and Why does the Efficiency of Regional Innovation Systems Differ? Februar. 02/6 Horst Brezinski, Peter Seidelmann, Unternehmen und regionale Entwicklung im ostdeutschen Transformationsprozess: Erkenntnisse aus einer Fallstudie, März. 02/7 Diana Grosse, Ansätze zur Lösung von Arbeitskonflikten das philosophisch und psychologisch fundierte Konzept von Mary Parker Follett, Juni. 02/8 Ursula Walther, Das Äquivalenzprinzip der Finanzmathematik, Juli. 02/9 Bastian Heinecke, Involvement of Small and Medium Sized Enterprises in the Private Realisation of Public Buildings, Juli. 02/10 Fabiana Rossaro, Der Kreditwucher in Italien Eine ökonomische Analyse der rechtlichen Handhabung, September. 02/11 Michael Fritsch, Oliver Falck, New Firm Formation by Industry over Space and Time: A Multi-Level Analysis, Oktober.

14 02/12 Ursula Walther, Strategische Asset Allokation aus Sicht des privaten Kapitalanlegers, September. 02/13 Michael B. Hinner, Communication Science: An Integral Part of Business and Business Studies? Dezember /01 Bruno Schönfelder, Death or Survival. Post Communist Bankruptcy Law in Action. A Survey, Januar. 03/02 Christine Pieper, Kai Handel, Auf der Suche nach der nationalen Innovationskultur Deutschlands die Etablierung der Verfahrenstechnik in der BRD/DDR seit 1950, März. 03/03 Michael Fritsch, Do Regional Systems of Innovation Matter? März. 03/04 Michael Fritsch, Zum Zusammenhang zwischen Gründungen und regionaler Entwicklung, April. 03/05 Tessa Rülke, Erfolg auf dem amerikanischen Markt 03/06 Michael Fritsch, Von der innovationsorientierten Regionalförderung zur regionalisierten Innovationspolitik, erscheint in: Michael Fritsch (Hrsg.): Marktdynamik und Innovation Zum Gedenken an Hans-Jürgen Ewers, Berlin 2004: Duncker & Humblot. 03/07 Isabel Opitz, Michael B. Hinner (Editor), Good Internal Communication Increases Productivity, Juli. 03/08 Margit Enke, Martin Reimann, Kulturell bedingtes Investorenverhalten Ausgewählte Probleme des Kommunikations- und Informationsprozesses der Investor Relations, September. 03/09 Dieter Jacob, Christoph Winter, Constanze Stuhr, PPP bei Schulbauten Leitfaden Wirtschaftlichkeitsvergleich, Oktober. 03/10 Ulrike Pohl, Das Studium Generale an der Technischen Universität Bergakademie Freiberg im Vergleich zu Hochschulen anderer Bundesländer (Niedersachsen, Mecklenburg-Vorpommern) Ergebnisse einer vergleichenden Studie, November /01 Michael Fritsch, Pamela Müller, The Effects of New Firm Formation on Regional Development over Time, Januar. 04/02 Michael B. Hinner, Mirjam Dreisörner, Antje Felich, Manja Otto, Business and Intercultural Communication Issues Three Contributions to Various Aspects of Business Communication, Januar.