Using Police Data to Analyse Juvenile Re-offending in Western Australia, 2013 to 2019

Ms Christine Mccomb1

1Western Australia Police, Perth, Australia

Baseline analysis of Police data was undertaken addressing juvenile reoffending in Western Australia. Reoffending was defined as an individual being ‘identified as an offender’ on multiple days. This goes beyond traditional conviction- or charge-based definitions of reoffending and moves towards evaluating ‘repeated contact with Police’, encompassing diversionary outcomes as well as formal sanctions.

Using data from 2013 – 2019, the analysis focused on the prevalence, speed and demographics associated with reoffending as recorded by Police. 27,333 children and juveniles were recorded as offenders between 2013 and 2018. 47% were identified as reoffenders, with this cohort responsible for the majority of offences and crime harm in any given year.

Trajectories were distinctly different for Aboriginal and non-Aboriginal youth.

Where offenders’ first known offence occurred in 2013 – 2018, 32% of Aboriginal juvenile offenders reoffended within six months, 32% had reoffended. In comparison, only 18% of non-Aboriginal juveniles reoffended within six months, and 35% within one year. Within five years of their first recorded offence, 70% of Aboriginal young offenders had reoffended.

For both groups, earlier age of onset was associated with higher rates and severity of reoffending. As repeat offending increased the likelihood of being prosecuted, rather than diverted, increased, and prosecution was associated with higher rates of subsequent reoffending and faster reoffending than diversion.

The pros and cons of using such a definition of reoffending will be discussed, along with practical implications of adopting ‘reoffending’ as an (internal or external) outcome measure for law enforcement agencies.


Christine McComb joined the WA Police Evidence Based Policing Division (now the Office of Applied Criminology) in 2015 after working in WA Police State Intelligence for four years. Her current role as Data Analytics and Assessment officer involves research design, evaluation and assistance for a range of Evidence Based Policing projects.

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