Source: (2004) IN, George Mair,ed., What Matters in Probation?. Cullompton, Devon,UK: Willan Publishing. Pp. 187-209.Over the last several decades, research studies into the outcomes of probation supervision have gradually identified various factors that correlate with rates of successful completion of probation orders and rates of failure to complete those orders. Factors include age, gender, and criminal history. Through the 1970s, there was little to indicate that probation-based interventions positively affected rates of completion. Age, gender, and criminal history seemed far more determinative. More recent studies have placed greater emphasis on assessing the outcomes of specific, cognitive-behavioral interventions (e.g., specific programs or activities) rather than 'generic' probation. Against this background, Stephen Farrall discusses a research project called Tracking Progress on Probation. This research sought an understanding of processes that occurred during probation orders that fostered either desistance from crime or persistence in crime. In reporting the main findings of the research, Farrall highlights the complex and interdependent relationships between the variables of social context, motivation, and probation supervision in desistance or persistence.