Abstract
This thesis considers how research evidence can support the probation service in its work with offenders, addressing the questions: 'What methods are effective in offender rehabilitation?'; 'How can we know these methods are working in practice?' and 'How can research evidence underpin policy and practice in work with offenders?'. The thesis explores whether crime-reduction via work with individual offenders is a feasible aim, ethically and practically, and reviews how this fits with theoretical approaches to understanding crime, and as an aim of the probation service. The characteristics of effective and ineffective methods of intervention as described in research literature are reviewed, revealing a low level of consistency between research-syntheses as to the characteristics of effective interventions. Methods of research synthesis and meta-analysis are critically reviewed. Issues in evaluating offender-interventions are reviewed, focusing on the use of reconviction as an outcome indicator. The thesis presents research case-studies of five offender-interventions, selected to be representative of probation programmes. The impact of each intervention on reconviction is evaluated using a quasi-experimental methodology. The offending careers of over 700 offenders, in intervention and comparison groups, are analyzed. Three interventions show clear evidence of effectiveness, with a lower proportion of offenders in the intervention groups than in relevant comparison groups being reconvicted: 48 percent, 34 percent (these finding were statistically significant), and 18 percent fewer offenders in the intervention group were reconvicted within one year. In this latter case-study of an evidence-based cognitive-skills training programme, offenders who showed positive change in attitudinal measures were more likely to be reconvicted. The implications of this finding for programme-evaluation methods are discussed. The thesis concludes by considering what these findings convey about effective ways of working with offenders, and how the findings contribute to an evidence-based approach in the probation service's work with offenders.