In defence of multidimensional scaling for the analysis of sexual offence behaviour: cautionary notes regarding analysis and interpretation

Abstract

Multidimensional scaling (MDS) has become a popular form of statistical analysis in the field of psychology and law. A recent paper in this journal by Sturidsson and colleagues (12, 221–230, 2006) used MDS to replicate an earlier study of sexual offence behaviour by Canter and Heritage (Journal of Forensic Psychiatry, 1, 185–212, 1990). They concluded that the model was not replicable and cast grave doubts on the applicability of MDS for the analysis of sexual offences. In this paper I argue that neither conclusion is correct. Initial difficulties in interpretation of the MDS results were clearly due to errors in calculation that should have been recognised. Indeed, a frequency analysis of Sturidsson and colleagues’ variables indicated that their results were in fact remarkably congruent with those of Canter and Heritage. It is concluded that statistical software should not obviate the need for a working knowledge of the statistics being computed.