Prof. Mark Kebbell1, Mr Boyd Potts, Associate Professor Carleen Thompson, Dr James Ogilvie, Ms Lindsy Lethbridge, Ms Rebecca Howard
1Griffith University, Brisbane South, Australia
Biography:
Mark Kebbell is Professor of Forensic Psychology at the School of Applied Psychology, Griffith University. His expertise and research is in the area of Investigative Psychology particularly with regards the investigation and prosecution of serious crime. His previous work has included writing the guidelines for police officers in England and Wales (with Wagstaff) for assessing witness evidence, and developing risk assessment methods for suspected sex offenders for the Australian Federal Police and the Queensland Police Service.
Abstract:
A small proportion of offenders are responsible for a disproportionate share of serious crime harm. This reflects the Pareto Principle, whereby approximately 20% of inputs account for 80% of outcomes. While this phenomenon is well recognised, less is known about the characteristics and offending pathways of those responsible for the greatest levels of harm. This presentation uses Queensland Police Service data to examine the concentration of crime harm across offenders. For each offender, the cumulative harm associated with all ‘solved’ offences was calculated using an adapted version of the Western Australian Harm Index. Harm was then aggregated across offender percentiles to quantify the extent to which a small number of offenders account for total harm. To better understand patterns of offending, hierarchical cluster analysis was conducted across 16 offence categories, including violent, sexual, property, drug, weapons, traffic, justice, and domestic violence-related offences. The resulting clusters identify distinct offender typologies based on offending profiles rather than offence frequency alone. By combining a harm-based measure with offender typologies, this study moves beyond traditional counts of offending to identify those individuals responsible for the greatest societal harm. The findings provide new insights into pathways into harmful offending and highlight opportunities for more targeted prevention, intervention, and offender management strategies. Focusing resources on the relatively small group of offenders responsible for the greatest harm has the potential to improve the effectiveness of policing and enhance community safety.