ILSE is an interdisciplinary longitudinal study that offers the opportunity to analyze inter- and intra-individual differences and changes over the life-span as well as relations between environmental factors, behavioral aspects, life-events, health behaviors, mental and physical health and well-being. The bio-graphical approach pursued by the ILSE-study is based on the assumption that the quality of developmental experiences in early life-phases influence the performance and possibilities of adaptation in later life in a unique way.

At the first measurement point, the ILSE sample consisted of 1390 persons from East (re-search centres: Leipzig and Rostock) and West Germany (research centres: Heidelberg, Bonn and Erlangen-Nuremberg). Stratified by sex and cohort membership (born 1930-32 and 1950-52, respectively) the representative ILSE-sample was examined by a interdisciplinary research team. The first round of data collection was conducted between 1993 and 1996, the second round with n = 994 participants from the data collection centres Heidelberg, Leipzig und Rostock (return rate = 90%) was conducted between 1997 and 2000. The third round of data collection which started in January 2005 ended in 2007. A fourth wave was conducted and completed between 2014 and 2016