MDS use with crime scene data replicates poorly: response to Goodwill,Alison, and Humann (this issue) and Davis (this issue)

Abstract

Examinations of treatment attrition form an important – although sometimes neglected – component of evaluating a correctional programme's effectiveness in reducing recidivism. Previous research has identified offender characteristics that predict non-completion. This study investigated non-completion in 138 high-risk, violent male prisoners attending an intensive cognitive–behavioural programme. Almost one-third of men who commenced it did not complete the 7-month programme. Most asked to leave of their own accord, or were removed for ongoing offending. In contrast to previous research, no support was found for the hypothesis that those who terminated treatment prematurely were more in need of intervention than those who completed the programme; non-completers did not differ from completers on static estimates of criminal risk, PCL-R scores, demographic variables or self-report scales measuring dynamic risk factors. It was concluded that successful prediction using variables related to criminal risk and criminogenic need depends both on the characteristics of programme participants, and on contextual factors such as programme policies: when high-risk high needs offenders are a programme's target clientele, variables related to risk and need will have limited predictive utility. From a practice perspective, the programme was successful in retaining through to completion a relatively untreatable group: high-risk offenders with moderate to high PCL-R scores.     

Using multidimensional scaling for the analysis of sexual offence behaviour: A replication and some cautionary notes

Abstract

Crime scene profiling has received considerable attention, particularly in popular media. First, since low inter-rater reliability would affect the validity of profiling, we tested inter-rater agreement for 33 variables often used in manuals for the coding of crime-related behaviour. Thirty cases were chosen randomly from 146 cases of assault rape with unknown male offenders in Sweden during 1990–1994. Second, we used multidimensional scaling (MDS) with all 146 cases to replicate earlier work by Canter and Heritage (Journal of Forensic Psychiatry, 1, 185–212, 1990) regarding motivational dimensions in unknown assault rapists. On average, inter-rater reliability was good; physical behaviours were more reliably coded than were verbal behaviours. However, a two-dimensional MDS solution with the motivational dimensions suggested by Canter and Heritage was not replicated. We argue for better empirical support for the inclusion of specific variables in coding formats for crime scene information. This is particularly important for analyses like the MDS, since the number, representativity, and intercorrelations of such variables could affect results considerably.