‘Citizenship’ is a structured probation supervision program based on ‘what works’ principles, designed for offenders on community orders or licenses supervised within the UK National Probation Service. The program was evaluated using survival analysis comparing the reconvictions of a cohort of all offenders in one probation area eligible for Citizenship over a 2-year period (n = 3,819) with those of a retrospective cohort of all eligible offenders in the same probation area receiving ‘traditional’ probation supervision (n = 2,110), controlling for risk related factors. At the 2-year stage, 50% of offenders in the comparison group had reoffended compared to 41% in the experimental group, and the difference between the survival curves was statistically significant. The hazard ratio was 0.69, which represents a 31% reduction in reconvictions in the experimental group over the proportion in the comparison group at any given time. Time to violation of a supervision order or post custody license was also statistically significantly longer in the experimental group. A key element of the program, promoting contact with community support agencies, was statistically significantly related to reduced reoffending in the Citizenship group. The overall effects remained after controlling for differences in risk scores although effectiveness varied by risk level. Contrary to other ‘what works’ research findings, the program was found to be most effective across the low–medium and medium–high risk thresholds, and was not effective with the highest risk group. This difference can be explained and is discussed in terms of risk, need, and responsivity principles. The Citizenship program was found to be cost-beneficial.