By the time you read this, fieldwork will have already begun for SOEP’s 25th wave. Next year this will allow you as a researcher to evaluate approximately 2,500 records on individuals who have participated in our survey every year since 1984, for a total of 25 times (West German Subsamples A and B). In the year 2009, we will already be collecting the 20th wave of Subsample C in the former East Germany. And in 2010 our most recent subsample (Refresher Sample H) will already be in its 5th year. No one could have imagined the success and duration of SOEP in the early 1980s, when the concept for this longitudinal study was developed and the funding first provided (starting in 1982). This can be seen clearly in the recollections of SOEP founder Hans-Jürgen Krupp (see SOEPpaper No. 75). He also makes reference to numerous colleagues who provided invaluable contributions to getting the SOEP survey underway. The SOEP user conference (SOEP2008) on July 9-11, 2008, will allow us another opportunity to thank them personally.
What 25 waves of SOEP can potentially mean is also revealed, for example, in the fact that in the year 2008, the eighth age cohort born into SOEP will already reach the survey age of 17 (in total, the 1984 to 1991 birth cohorts up to now). Also in 2008, a questionnaire for pre-schoolers will go into the field for the first time - the third “age-triggered” questionnaire for children (in addition to the questionnaires about newborn babies and toddlers). The new questionnaire will be given to those children whose mothers were first interviewed about their newborn babies in the year 2002 on questions of pregnancy, birth, and the first months of the child’s life. And since 2005, SOEP has also included a questionnaire for two to three-year-olds.
In the meantime, the SOEP data set contains over 1,000 “SOEP grandchildren”, whose parents and grandparents are former or present SOEP participants. Thus, SOEP has taken on a unique significance for the analysis of inter-generational relationships. Even now, approximately 100 of SOEP’s grandchildren have already reached survey age themselves. This a good example of how the value of the data set increases with each subsequent wave. The constant expansion of the dataset through the addition of further, more detailed information on subjects covered by SOEP offers researchers the opportunity to conduct cutting-edge analyses adapted to current needs and issues. And the longer SOEP runs, the more analytical power the data set will gain.
Not only have SOEP data made it possible to produce interesting scientific findings and robust policy advice; the many longitudinal analyses conducted on the basis of SOEP have also led to an increase in the collection of high quality panel data worldwide. We are delighted that SOEP has served as a role model for other scientific studies such as the recently launched Australian household panel HILDA, which is structurally very similar to SOEP. At the same time, we are proud that other German panel studies, such as the “National Education Panel” which is currently being developed to study school and professional competencies, are founded not least of all on the experiences that political decision-makers have gathered through their experience with SOEP.
This is true as well for the IAB (Institute for Employment Research) panel on “Low Income Households”.
Last but not least, the SOEP experiences have provided a significant impetus for developments in the UKLHS, the UK Longitudinal Household Panel Study. The UKLHS pretest (known as the “innovation panel”) is in the field this year. Its battery of questions is significantly broader than that of the BHPS (British Household Panel Study), which started in 1991. It will, for example, integrate new kinds of questions on psychologocial concepts such as risk attitudes and trust. This is no coincidence, given the steadily growing importance of interdisciplinary data in the social and behavioral sciences (see also the essay by Frick, Schupp and Wagner in Schmollers Jahrbuch (PDF, 173.3 KB)).
Household panel data were initially collected mainly with the goal of providing policy advice. This orientation has changed fundamentally. Today more than ever before, household data serve the purposes of basic research. As a result, for the SOEP group in Berlin, close cooperation and research relationships with universities and other research institutes are becoming ever more important. The SOEP team in Berlin is working to improve the analytical power of SOEP by expanding our cooperation further than ever before. A particularly noteworthy achievement in this regard is our increasingly close cooperation with the Max Planck Institute for Human Development, a relationship that underscores the importance of SOEP data for questions of lifespan development and individual life courses.
For many years, we have been inviting our users to contribute suggestions for the SOEP questionnaire. In this, our birthday year, we would like to implore our users more than ever to contribute their ideas - not only for the questionnaire itself but also for the entire design of SOEP. As SOEP users, you are well aware that we were constantly adding new subsamples and changing survey processes. Please give us your ideas and suggestions for the further development of SOEP and let’s talk about them together. Workshops for deeper discussions are possible too. However, we have never added research questions merely because they were of ad-hoc interest; again and again over the years, we have added new issues only when they fit into the longitudinal design of SOEP. And although we may not always have added questions as fast as some of the proposers would like, once we have done so, the additions often become a permanent part of the questionnaire, such as our improved questions on fringe benefits.
We as the SOEP team in Berlin-like the Infratest Sozialforschung team in Munich-have never made a big to-do out of birthdays. We prefer to put our energy into improving and developing the SOEP study further. This year will be no different. Our chief goal is to use new theoretical developments and methods of data collection and measurement to further improve the analytical power of SOEP. But at the 8th International User Conference in July 2008, we of course want to celebrate our birthday with you, and some of the sessions will pay tribute to this event. Please consider this event when setting up your schedule for 2008, and consult the conference homepage for updated information.
Without your intensive and innovative research work, 25 waves of SOEP would have been unthinkable. SOEP’s success is a shared success of our global research community!
Gert G. Wagner
The Knight’s Cross of the Order of Merit of the Federal Republic of Germany has been conferred on Gert Wagner on February 8th, 2008.