Crime linkage of sex offences in Japan by multiple correspondence analysis
Journal of Investigative Psychology and Offender Profiling
Published online on October 10, 2016
Abstract
This study examined the effectiveness of multiple correspondence analysis (MCA) for linking crimes. The data consisted of 720 incidents committed by 360 individual offenders of serial criminal sexual contact cases (i.e., rape and forced indecency). According to the measured similarity obtained from the Euclidean distance in the MCA configuration, a rank‐score was assigned to each linked pair and unlinked pair. The validity of MCA for linking crimes was evaluated with a 10‐fold cross‐validation procedure and a receiver operating characteristic analysis. The t‐test of rank scores showed a statistically significant difference between linked pairs and unlinked pairs (t(641.43) = −18.53, p < .001, d = 1.38). The value of the area under the receiver operating characteristic curve was .83 (95% CI = .80–.86), indicating a high level of discriminative accuracy in distinguishing offences committed by the same person from those committed by different persons.