Linking crimes using behavioural clues: Current levels of linking accuracy and strategies for moving forward

The number of published studies examining crime linkage analysis has grown rapidly over the last decade, to the point where a special issue of this journal has recently been dedicated to the topic. Many of these studies have used a particular measure (the area under the receiver operating characteristic curve, or the AUC) to quantify the degree to which it is possible to link crimes. This article reviews studies that have utilised the AUC and examines how good we are currently at linking crimes (within the context of these research studies) and what factors impact linking accuracy. The results of the review suggest that, in the majority of cases, moderate levels of linking accuracy are achieved. Of the various factors that have been examined that might impact linking accuracy, the three factors that appear to have the most significant impact are crime type, behavioural domain, and jurisdiction. We discuss how generalisable these results are to naturalistic investigative settings. We also highlight some of the important limitations of the linking studies that we reviewed and offer up some strategies for moving this area of research forward.