Official and administrative data can provide a constructed and misleading image of offending behaviour of youngsters. Self-report studies were invented precisely to escape these limitations and to expose juvenile delinquent behaviour beyond judicial registration. In Belgium (official) systematic national self-report data are not available. Since the 1970s, self-report research has been carried out by different official as well as academic stakeholders (Born 1987; Goedseels et al. 2000; Junger-Tas 1976; Junger-Tas et al. 1994; Spaey 2004; Vercaigne et al. 2000; Vettenburg et al. 2007). For the Flanders region there is the repeated (2005-2006; 2008; 2013) self-report survey of the JOP—Jeugdonderzoeksplatform (Pleysier 2014; Pleysier and Put 2015). Hence, these studies use different survey instruments, target different delinquent or problematic behaviour and different age groups and were used with very different population samples. Therefore, Belgian selfreport data are difficult to compare over time and space. However, Belgian researchers participated in the subsequent ISRD 1, 2 and 3 (Gavray and Vettenburg). Although there are some publications for the first and second ISRD survey concerning the Belgian sample, no overview concerning the results of the most recent sample (2012-2016) is available. Some results have been presented at international conferences, but have not been published yet.
It is clear that this lack of (uniform) data collection, a well-known and ongoing problem in Belgium, turns scientific research on trends in, but also on the causes of, youth delinquency into a difficult and hazardous endeavour. Critics might even wonder on the basis of what information the federal and community governments actually shape their juvenile justice policies.