Samenvatting

The aim of this study was to provide more insight in prevalence and aetiology of juvenile frequent offending, employing police registered data as well as self-report information. We combined data about 519 youths that participated in a self-report study in the region of The Hague with police register data (the HKS system) from the police unit of The Hague. The results indicate that a substantial part of youths that report a large amount of offenses themselves are not formally known as ‘juvenile frequent offender’. Causal factors derived from four major criminological theories can be found in a more pronounced way among juvenile frequent offenders than among youths that incidentally commit offenses. In general, there are similarities between the characteristics of juvenile frequent offenders defined by police register data and those defined by self-reports, but, on average, frequent offenders that are known by the police spend more time unstructured socializing with friends. We conclude that research using the method of self-report is well capable to find juvenile frequent offenders, and that this method also leads to useful information about the causes of their delinquent behaviour.