Evaluation of police crime prevention measures for persistent offenders in the German state of North Rhine-Westphalia

Recent years have seen the development of a range of concepts throughout Germany addressing how the police should deal with persistent offenders in order to reduce the amount of offending. The State Office of Criminal Investigations in North Rhine-Westphalia commissioned an evaluation of the concepts applied in four different district police authorities in the state. The offence records of almost 300 young persistent offenders from the year they entered until the year they left the program were compared with those of a matched control group with a similarly high rate of offending who were not included in the measures. The summative evaluation showed a higher reduction in crime in the treatment group compared to controls by a factor of 1.31 with an effect size of d = 0.26. Further analyses indicated the effect of the program was independent of the persistent offenders' age, gender or migration status. The discussion on this positive outcome focuses on the methodological problems in the study and also on the very low intensity of the measures compared to other offender treatment programs.