OBJECTIVE: An international network study involving parallel, complementary interventions in three EU countries and an associate country (Germany, United Kingdom, The Netherlands and Norway) is reported. The aim is to develop a unified approach to the assessment of social risk and related behaviours in offender groups. METHOD: The Behavioural Status Index (BEST-Index) and a set of cross-validating instruments (PCL-R, HCR-20; SCL-90-R; BDHI-D) were applied to a sample of n = 231 mentally ill offenders. RESULTS: Selected results using a sub-sample of n = 89 German offenders are reported and discussed. CONCLUSIONS: The BEST-Index shows convergent validity with respect to a social risk criterion and it helps to determine an objective data base for the improvement of carer assessments, related care planning, and delivery.