Sex offenders are on the move

Convicted sex offenders continue to move freely within communities, including in restricted areas, despite laws designed to limit their movements. A new study, by Alan Murray from Arizona State University and colleagues, uses new tracking techniques to better understand the actual movements of sex offenders. This information can help develop effective strategies to promote public safety. The findings are published in a new book, Crime Modeling and Mapping Using Geospatial Technologies, published by Springer.

Sexual offenses, especially those committed against children, are of concern to both the public and policy makers. In response to these concerns, local, state and federal legislators in the US have passed a series of laws designed to reduce interaction between children and these potentially dangerous individuals. To date, the vast majority of research on sex offenders and residence restrictions deals with issues of housing availability and affordability. Very little work has focused on sex offender mobility, and residence trends in particular.

Murray and his team analyze sex offender residential movement patterns over a two and a half year period in Hamilton County, Ohio. They used geographic information systems and a developed exploratory system (SOSTAT)* to uncover spatial behavioral patterns, which give important insights into offender reintegration, their mobility within communities and the implications of restrictions on both offenders and the community.

Their analyses showed that sex offenders appear to be a very mobile group. Over the two and a half year period, 65 percent of registered offenders changed residences. Although there was a noticeable trend towards fewer offenders living in restricted zones overall, worryingly, nearly a third moved from non-restricted areas into restricted zones.

The authors conclude: "Over the years, changes in laws governing post-release activities of offenders were designed to monitor and track this group of individuals. Our study highlights that, despite these increasingly stringent laws, sex offenders move freely about communities and continue to reside in restricted residential areas. This mobility suggests that current policies may require modification to achieve their intended goals."

This example of the value of spatial analysis for crime analysis is featured in a new book Crime Modeling and Mapping Using Geospatial Technologies edited by Michael Leitner of Louisiana State University in Baton Rouge (USA). The book tackles various types of crime and places them in a geospatial context. As well as posing interesting questions on crime in such a context, the chapters also discuss applications and implementations of geographic information systems.