Econometric models are made up of assumptions which never exactly match reality. Among the most contested ones is the requirement that the coefficients of an econometric model remain stable over time. Recent years have therefore seen numerous attempts to test for it or to model possible structural change when it can no longer be ignored. This collection of papers from Empirical Economics mirrors part of this development. The point of departure of most studies in this volume is the standard linear regression model Yt = x;fJt + U (t = I, ... , 1), t where notation is obvious and where the index t emphasises the fact that structural change is mostly discussed and encountered in a time series context. It is much less of a problem for cross section data, although many tests apply there as well. The null hypothesis of most tests for structural change is that fJt = fJo for all t, i.e. that the same regression applies to all time periods in the sample and that the disturbances u are well behaved. The well known Chow test for instance assumes t that there is a single structural shift at a known point in time, i.e. that fJt = fJo (t< t*), and fJt = fJo + t1fJ (t"?:. t*), where t* is known.

Scan 2000, the GAMM - IMACS International Symposium on Scientific Computing, Computer Arithmetic, and Validated Numerics and Interval 2000, the International Conference on Interval Methods in Science and Engineering were jointly held in Karlsruhe, September 19-22, 2000. The joint conference continued the series of 7 previous Scan-symposia under the joint sponsorship of GAMM and IMACS. These conferences have traditionally covered the numerical and algorithmic aspects of scientific computing, with a strong emphasis on validation and verification of computed results as well as on arithmetic, programming, and algorithmic tools for this purpose. The conference further continued the series of 4 former Interval conferences focusing on interval methods and their application in science and engineering. The objectives are to propagate current applications and research as well as to promote a greater understanding and increased awareness of the subject matters. The symposium was held in Karlsruhe the European cradle of interval arithmetic and self-validating numerics and attracted 193 researchers from 33 countries. 12 invited and 153 contributed talks were given. But not only the quantity was overwhelming we were deeply impressed by the emerging maturity of our discipline. There were many talks discussing a wide variety of serious applications stretching all parts of mathematical modelling. New efficient, publicly available or even commercial tools were proposed or presented, and also foundations of the theory of intervals and reliable computations were considerably strengthened.

This Festschrift is dedicated to Goetz Trenkler on the occasion of his 65th birthday. As can be seen from the long list of contributions, Goetz has had and still has an enormous range of interests, and colleagues to share these interests with. He is a leading expert in linear models with a particular focus on matrix algebra in its relation to statistics. He has published in almost all major statistics and matrix theory journals. His research activities also include other areas (like nonparametrics, statistics and sports, combination of forecasts and magic squares, just to mention afew). Goetz Trenkler was born in Dresden in 1943. After his school years in East G- many and West-Berlin, he obtained a Diploma in Mathematics from Free University of Berlin (1970), where he also discovered his interest in Mathematical Statistics. In 1973, he completed his Ph.D. with a thesis titled: On a distance-generating fu- tion of probability measures. He then moved on to the University of Hannover to become Lecturer and to write a habilitation-thesis (submitted 1979) on alternatives to the Ordinary Least Squares estimator in the Linear Regression Model, a topic that would become his predominant ?eld of research in the years to come.

The major emphasis of the Dagstuhl Seminar on "Numerical Validation in C- rent Hardware Architectures" lay on numerical validation in current hardware architecturesand softwareenvironments. The generalidea wasto bring together experts who are concerned with computer arithmetic in systems with actual processor architectures and scientists who develop, use, and need techniques from veri?ed computation in their applications. Topics of the seminar therefore included: - The ongoing revision of the IEEE 754/854 standard for ?oating-point ari- metic - Feasible ways to implement multiple precision (multiword) arithmetic and to compute the actual precision at run-time according to the needs of input data - The achievement of a similar behavior of ?xed-point, ?oating-point and - terval arithmetic across language compliant implementations - The design of robust and e?cient numerical programsportable from diverse computers to those that adhere to the IEEE standard - The development and propagation of validated special-purpose software in di?erent application areas - Error analysis in several contexts - Certi?cation of numerical programs, veri?cation and validation assessment Computer arithmetic plays an important role at the hardware and software level, when microprocessors, embedded systems, or grids are designed. The re- ability of numerical softwarestrongly depends on the compliance with the cor- sponding ?oating-point norms. Standard CISC processors follow the 1985 IEEE norm 754, which is currently under revision, but the new highly performing CELL processor is not fully IEEE compliant.

This Festschrift is dedicated to Goetz Trenkler on the occasion of his 65th birthday. As can be seen from the long list of contributions, Goetz has had and still has an enormous range of interests, and colleagues to share these interests with. He is a leading expert in linear models with a particular focus on matrix algebra in its relation to statistics. He has published in almost all major statistics and matrix theory journals. His research activities also include other areas (like nonparametrics, statistics and sports, combination of forecasts and magic squares, just to mention afew). Goetz Trenkler was born in Dresden in 1943. After his school years in East G- many and West-Berlin, he obtained a Diploma in Mathematics from Free University of Berlin (1970), where he also discovered his interest in Mathematical Statistics. In 1973, he completed his Ph.D. with a thesis titled: On a distance-generating fu- tion of probability measures. He then moved on to the University of Hannover to become Lecturer and to write a habilitation-thesis (submitted 1979) on alternatives to the Ordinary Least Squares estimator in the Linear Regression Model, a topic that would become his predominant ?eld of research in the years to come.

Scan 2000, the GAMM - IMACS International Symposium on Scientific Computing, Computer Arithmetic, and Validated Numerics and Interval 2000, the International Conference on Interval Methods in Science and Engineering were jointly held in Karlsruhe, September 19-22, 2000. The joint conference continued the series of 7 previous Scan-symposia under the joint sponsorship of GAMM and IMACS. These conferences have traditionally covered the numerical and algorithmic aspects of scientific computing, with a strong emphasis on validation and verification of computed results as well as on arithmetic, programming, and algorithmic tools for this purpose. The conference further continued the series of 4 former Interval conferences focusing on interval methods and their application in science and engineering. The objectives are to propagate current applications and research as well as to promote a greater understanding and increased awareness of the subject matters. The symposium was held in Karlsruhe the European cradle of interval arithmetic and self-validating numerics and attracted 193 researchers from 33 countries. 12 invited and 153 contributed talks were given. But not only the quantity was overwhelming we were deeply impressed by the emerging maturity of our discipline. There were many talks discussing a wide variety of serious applications stretching all parts of mathematical modelling. New efficient, publicly available or even commercial tools were proposed or presented, and also foundations of the theory of intervals and reliable computations were considerably strengthened.

Dieser Sammelband zeigt an ausgewahlten Beispielen, wie spannend und vielfaltig statistische Forschung sein kann. Ob es nun darum geht, hoergeschadigten Menschen einen guten Musikgenuss zu verschaffen, aus Texten sinnvolle quantitative Daten zu extrahieren oder UEberschwemmungskatastrophen zu modellieren und damit besser in den Griff zu bekommen - die meisten in diesem Buch dargestellten Erkenntnisse sind nicht in Lehrbuchern zu finden, sie stammen direkt von der Forschungsfront und laden zum Staunen und Entdecken ein. Auf Fachjargon und Formalismus wird bei der Darstellung so weit wie moeglich verzichtet - das Buch richtet sich somit an jeden, der sich fur das aktuelle Forschungsgeschehen im Bereich statistischer Anwendungen interessiert. Es ermoeglicht einen unverdeckten Blick auf eine durch und durch faszinierende Wissenschaft - ohne dass die einzelnen Analysen bis ins Detail nachvollzogen werden mussen. Studierenden kann das Buch helfen, Begeisterung fur statistische Fragestellungen und Methoden zu entwickeln, oder sogar Anregungen fur die eigene Laufbahn geben. Ein Grossteil der Beitrage entstand an der Fakultat Statistik der TU Dortmund, der einzigen eigenstandigen Statistik-Fakultat im ganzen deutschen Sprachgebiet, sowie daruber hinaus im Rahmen von an diese Fakultat angedockten DFG-Sonderforschungsbereichen.

Das Programmpaket SAS hat sich im Lauf der Jahre als Standardprogramm zur statistischen Datenanalyse etabliert. Der souverane Umgang mit statistischen Methoden und deren praktischer Umsetzung in SAS bietet somit einen unschatzbaren Vorteil fur die tagliche Arbeit des Datenanalytikers. Im vorliegenden Buch erlernt der Leser zunachst die Grundlagen fur die Programmierung. Anschliessend wird eine grosse Auswahl statistischer Verfahren und deren Umsetzung als SAS-Programm vorgestellt. Dabei wird grosses Augenmerk auf die grafischen Aspekte der statistischen Datenanalyse gelegt. Ein zusatzlicher Teil uber Programmierung mit IML und Makros sowie hilfreiche Assistenten in SAS runden die Darstellung ab. Mit seiner umfassenden Themenauswahl ist das Buch als Einfuhrung, aber auch als Nachschlagewerk fur den fortgeschritteneren Leser geeignet.

Der Band bietet eine allgemein verstandliche Ubersicht uber 100 Jahre Deutsche Statistische Gesellschaft (DStatG). In 17 Kapiteln schildern anerkannte Experten, wie die DStatG zur Begrundung und Fortentwicklung der deutschen Wirtschafts- und Sozialstatistik und zu methodischen Innovationen wie neuere Zeitreihen-, Preisindex- oder Stichprobenverfahren beigetragen hat. Weitere Themen sind die Rolle der DStatG bei der Zusammenfuhrung der Ost- und Weststatistik sowie die Vorbereitung und Durchfuhrung der letzen und der aktuellen Volkszahlung."

Das Buch nimmt die aktuelle Wirtschaftskrise zum Anlass, um die Frage nach der Qualitat der Presse, insbesondere der der Tageszeitungen zu stellen. Herzstuck des Buches sind aktuelle Beispiele, die veranschaulichen, dass Journalisten zu oft die Bedurfnisse der Leser missachten und schwer verstandliche Texte oder Uberschriften produzieren, die haufig nicht einmal interessant sind. Wer immer schon mal wissen wollte, warum ihn Wirtschaftstexte abschrecken, bekommt hier Antworten. Das Autorengespann zeigt gangige Auswahlfehler und kritisiert den Hang zum Dramatisieren und das Primat der Unterhaltung im Journalismus ebenso wie das in der Wirtschaftspresse grassierende Fachchinesisch und Burokratendeutsch. Die Autoren verstehen das Buch als Pladoyer fur einen guten Journalismus, damit die Medienverdrossenheit nicht noch weitere Kreise zieht.

Karsten Webel liefert einen UEberblick uber die in der OEkonometrie etablierten Erklarungsansatze fur ein langes Gedachtnis und weist erstmals nach, dass auch ein Prozess, der in diesen Gebiet nahezu unbekannt ist, unter bestimmten Bedingungen ein langes Gedachtnis erzeugen kann.

Die Statistik und ihre Anwendung in unserem Leben in 101 Stichwoertern kurz, pragnant und verstandlich erklaren kann nur Walter Kramer. Ob es um die Zusammensetzung der Arbeitslosenquote geht, Aktienkurse, Wahlprognosen, Intelligenzquotient, polizeiliche Kriminalstatistik oder um Klinische Studien und Big Data: Der Leser erhalt genau die Informationen, die er benoetigt, um im taglichen Leben mit Statistik sinnvoll umgehen zu koennen. Dazu muss man kein Rechen-As sein oder Mathematik studiert haben. Ein gesunder Menschenverstand und die Bereitschaft, den Tatsachen ohne Vorurteile ins Gesicht zu sehen reichen vollkommen aus, um die Kunst der Statistik schatzen zu lernen: den Schein vom Sein zu trennen und die Stecknadel im Heuhaufen zu finden. Dieses Buch ist ein gleichermassen verstandlicher, faszinierender, amusanter wie auch und hilfreicher als Ratgeber fur unseren taglichen Umgang mit Statistik: denn nur wer versteht kann mitreden und entlarven.