The self report study conducted in the cities of Münster and Duisburg, as well as in Bocholt in 2001, has the goal of explaining and monitoring the emergence and development of deviant and delinquent styles of behaviour throughout the phase of adolescence. As possible causes of these phenomena, the study focuses not only on structural conditions and processes on the macro-level, as for example the effects of social milieus, moral orientations, lifestyle, how spare time is spent, consumer attitudes as well as the effects of the social surroundings. It also focuses on individual processes which are embedded in different action theories, as for example theories of planned actions and cognitive emotional theories. Furthermore, the theoretical concept of the study includes social control, which can be located on the meso-level between the structural components of the macro-level and the action theories on the micro-level. This is, on the one hand, the formal social control by the police and the judiciary which defines what should be considered as delinquent behaviour in the first place. On the other hand, it is the informal control by school and parents who, at the same time, function as authorities for socialisation. The explanatory strength and empirical validity of these theoretical approaches will be examined individually as well as with regard to their interaction. This is because the described model postulates not only an effect of the macro-structures on decisions regarding action and cognitive processes on the individual levels, but also the constitution of macro-structures by processes on the individual level. By doing so, the aim is to produce an extensive explanatory report on deviance and delinquency of youths which reaches beyond the individual classical criminological theories.
In order to record delinquency specific developments of youths adequately, a combination of panel and cohort designs was chosen for the study. This should be an appropriate way of empirically analysing the very dynamic life phase of youth as well as the mostly episode-like appearances of youthful deviance. The significance of the chosen panel designs is that surveys are repeated annually and, each time, the same youths are questioned about their delinquent behaviour. This approach makes it possible to trace processes on the individual level for each survey instead of merely being able to provide details on the aggregate level. Furthermore, the design of the study has been extended from the panel- to a cohort design which enables comparisons of several age groups longitudinally. Additionally, a cohort comparison can be carried out which compares one age group at different points of time with subjects of different age cohorts. Within a cohort, individual patterns of delinquency can also be analysed throughout the survey’s different points of time as well.
In this prospective panel study, questionnaire interviews were carried out at schools in Münster in one-year intervals, starting in 2000 (seventh grade) and ending in 2003. In 2000, the ninth and eleventh grades were also interviewed. In 2001 in Bocholt, the seventh, ninth, and eleventh grades were interviewed. When the third round of the survey was conducted in Münster in 2003, when the youths had meanwhile reached the ninth grade, a first round of the survey was conducted in the seventh and ninth grades in Duisburg. Here, the aim was to create a parallel database for two age cohorts in order to control for cohort effects. In the first round a complete survey of the respective pupils in both cities was carried out in order to counteract the panel mortality and the accompanying strong reduction of the number of cases.
The survey of the youths who in 2002 were in the seventh grade in Duisburg will continue until 2019. Due to the fact of age-related school leaving, the mode of questioning was changed to a postal one. The survey of the older age cohort (ninth grade in 2002) was not continued in 2004 because of research economic reasons. The two rounds of the survey in 2002 and 2003 of the age group in Duisburg already provide a sufficient data basis for proving potential cohort effects in the younger cohorts (main panel). Altogether, the main focus of the combined cohort and panel study is thus on those youths from Münster who visited the seventh grade in 2000, and those youths from Duisburg who visited the seventh grade in 2002.
Furthermore, a comparison between the self-reported delinquency of the surveyed youths and the sanction data in the police registers as well as the educational registers, i.e. registered delinquency in the official registered crimes, is planned in both Münster and Duisburg.
An anonymized and over time an established-code oriented, hierarchical classification approach is used for classifying the questionnaires throughout the individual rounds of the survey. For this the participating youths each year fill out a personal code, which is requested in the questionnaire.