Source: (2004) IN, George Mair,ed., What Matters in Probation?. Cullompton, Devon,UK: Willan Publishing. Pp. 170-186.As the authors of this chapter remark, recent Home Office initiatives in the United Kingdom have placed What Works and effective interventions with offenders at the center of the probation service’s agenda. The transformation in this direction has been swift. This has led to some criticism that implementation has been forced before there is clear evidence of the value of this direction. Additionally, other questions have arisen around implementation of the What Works agenda. These include issues relating to probation service practice, management, and organization. Amid this, the authors argue the following in this essay: that the program-driven approach to the delivery of effective practice has obscured attention to those broader issues of implementation. They further contend that organizational and cultural challenges have been underestimated, and that this underestimation has resulted in low program completion rates in some areas and even broader difficulties in implementing effective practice.