​In September 2016 Jersey Probation and Aftercare Service (JPACS) was the subject of an evaluation to assess the extent to which its community supervision services adhere to principles of effective practice. The aims of this study were congruent with the Service’s intentions to reduce re-offending and produce reports to assist with policy formation. The CPAI-2010 (Gendreau, Andrews & Thériault, 2010) was used to assess nine domains of service delivery (eight of which are scored). The evaluation identified JPACS as having a number of strengths, achieving the highest possible rating of very satisfactory in every domain relating to effective practice and 100% scores in domains relating to the characteristics of management and staff, interagency communication and evaluation practices. This indicates that JPACS is currently well placed to deliver effective intervention services that reduce the reoffending of clients and, as a strong, professionalised service, to continue to develop these in response to the recommendations outlined in this report.