Issues likely to arise from the implementation of the What Works agenda are practice, management and organizational, with significant areas within each. This chapter argues that the program-driven approach to the delivery of effective practice has obscured attention to these broader issues of implementation and that organizational and cultural challenges have been underestimated causing low program completion rates and implementation difficulties for effective practice. Drawing on data collected approximately 15 months after the launch of the Home Office Effective Practice initiative, this research examined the first 12 weeks of supervision across the region to establish the extent to which practice was evidence led and based on What Works principles. A number of areas were examined and included: (1) assessment practices for both group and individual supervision; (2) content of supervision plans and group programs; (3) referral and induction practices; (4) the establishment of offender motivation and the maintenance of the change process; (5) measurements of program impact used by services; and (6) principles of resource allocation and actual use in the field. To achieve effective practice, a number of key considerations pertinent to the implementation were identified with the most significant being the pace of change, the level of central driving, and the unprecedented level of accountability and scrutiny on the service. The appropriate implementation of effective practice requires a strategic and whole system approach in which attention is given to the supporting processes, systems, and infrastructure required to ensure its effective delivery.