Sex offender clusters

In the United States, sex offender management strategies continue to receive significant public attention and scrutiny. In addition to federal and state mandated community notification laws, many locales are also implementing a variety of supplemental residence restrictions to protect sensitive facilities (e.g. schools) and combat the emergence of sex offender "clusters". Interestingly, while there are no generally accepted guidelines or municipal benchmarks for defining exactly what constitutes an offender cluster - subjective observation, and more generally, public perception appear to be the major inputs for cluster identification and related legislation. The purpose of this paper was to explore the utility of spatial statistical methods for objectively identifying sex offender clusters. Using offender registry data from the state of Illinois, a number of spatial applications are investigated which highlight the differences in clusters produced by each approach.