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Methodological Issues in Longitudinal Educational Studies

Starting position:

With the longitudinal studies LAU (Aspects of learning background and learning development) and KESS (Competencies and attitudes of students), the city of Hamburg has generated two data sets since 1995 which make the systematic analysis of performance progress in different subjects possible from the start of secondary level I up to the end of secondary level II. Due to the design of the longitudinal studies, both data sets are extremely complex. This is especially true of the performance data as they contain complex anchor-item-designs with linking items within and between measurement points.



Up until now, LAU and KESS have been documented extensively in predominantly descriptive reports. However, the student data also provides the opportunity to work in more depth on the methodological and substantial questions of longitudinal research. It was with this aim that the scientific consortium was founded in the summer of 2012 under the management of Prof. Olaf Köller.

The scientific consortium developed a number of projects. Five of these projects are now funded by the German Research Foundation (DFG).



  • The project of Michael Becker, Marko Neumann and Kai Maaz, Primary and Secondary Social Background Effects at Different Points of Transition in the Education System will focus primarily on social disparities in educational success. The researchers plan to examine the development of primary (achievement-related) and secondary (non-achievement-related) background effects at four junctures: at the transition from primary school to secondary school level I, after the so-called “observation level”, between secondary school levels I and II, and at the transition following level II of secondary school. The project will look at how primary and secondary effects change at the decision thresholds over the course of secondary school and how changes in educational demand (an increase in the number of students who have completed the Abitur examination between LAU and KESS) relate to patterns of inequality.


  • The project of Johannes Hartig, Eckhardt Klieme, Kai Maaz and Svenja Vieluf on Modeling Educational Effectiveness and Equity at the School Level focuses on school effectiveness and in this context also deals with social disparities. School effectiveness will be defined not only in terms of the quality of results, i.e. higher student achievement, but also in terms of equality of opportunity, i.e. the decoupling of social status and educational outcomes. The researchers will examine whether schools can be successful with regard to both the quality of their results and the degree to which they offer equal opportunity. In addition, they will identify structural and procedural characteristics of effective schools and, by comparing LAU and KESS, look at the degree to which a school’s outcome quality and equal opportunity remain stable over time. Accompanying methodological research planned within the project will focus on the reliability of model based criteria for school effectiveness.


  • In their project Bilingual Education and the Development of Academic Achievement, Cognitive Abilities, and Motivation in Secondary School: A Secondary Analysis of Data from the LAU and KESS Studies (BLUE-SKM), Jens Möller and Jürgen Baumert plan to focus on the language of instruction as a specific aspect of instructional quality. They will examine how lessons in selected subjects that are conducted in English as a foreign language over the course of secondary-school levels I and II affect student achievement in English, German and science, as well as motivation.


  • The project of Karin Guill and Olaf Köller, Conditions for Successful Tutoring: A Reanalysis of LAU and KESS Data, will also look primarily at the quantity and quality of instruction. In this case, however, the focus is on private tutoring, initiated by the family, rather than school-based instruction. The project will investigate the effects of a number of factors – length and intensity of tutoring, teacher qualifications, instructional content, teacher feedback, and students’ prior level of achievement – on successful learning and motivational variables, including academic self-concept, performance anxiety and work habits.


  • The project of Benjamin Nagengast and Ulrich Trautwein on Effects of Studying Abroad during High School – A Reanalysis of the LAU Study will also look at the effects of a measure initiated primarily by the family. The researchers will first examine significant factors related to the student and school that predict studying abroad. They will also look more closely at the effects of spending time in an English-speaking country on the development of English-language skills and Abitur results in English, differentiating among reading, writing and listening comprehension. They plan to expand their analysis to include other subjects, particularly mathematics.


Further subject areas are currently being developed.


Scientific Consortium:

Management: Prof. Dr. Olaf Köller, IPN / University of Kiel


Hamburg KESS/LAU-Team
Dr. Roumiana Nikolova
Stanislav Ivanov
Staatsrat a.D. Ulrich Vieluf

Humboldt-University, Berlin
Prof. Dr. Rainer H. Lehmann

IFS / TU Dortmund
Prof. Dr. Wilfried Bos

IPN / University of Kiel
Prof. Dr. Jürgen Baumert
Prof. Dr. Oliver Lüdtke
Prof. Dr. Gabriel Nagy

University of Hamburg
Prof. Dr. Knut Schwippert

DIPF / Berlin
Prof. Dr. Kai Maaz
Dr. Michael Becker
Dr. Marko Neumann

University of Tübingen
Prof. Dr. Ulrich Trautwein

Associated members:

IFS / TU Dortmund
Dr. Daniel Kasper
Dr. Heike Wendt

DIPF / Frankfurt
Prof. Dr. Johannes Hartig
Prof. Dr. Eckhard Klieme
Dr. Svenja Vieluf

IPN / Kiel University
Dr. Karin Guill

University of Potsdam
Prof. Dr. Michel Knigge

University of Tübingen
Prof. Dr. Benjamin Nagengast

Permanent guests in the scientific consortium:

IPN /  University of Kiel
Dr. Alexander Robitzsch

Humboldt-University, Berlin
Prof. Dr. Petra Stanat

University of Bamberg
Prof. Dr. Claus Carstensen

University of Jena
Prof. Dr. Andreas Frey

Dr. Karin Guill


Downloads: (in German)