Key factors increasing the risk of reoffending included the following:
- Age: as age increases the likelihood of recidivism declines.
- Prior prison admissions: each additional admission into prison increases the likelihood of further admissions occurring.
- Gender: males were more likely to reoffend compared to females.
- Aboriginal status: Aboriginal prisoners were more likely to reoffend compared to non-Aboriginal prisoners.
- Security Rating: maximum security prisoners were more likely to reoffend compared to medium security prisoners, who in turn were more likely to reoffend compared to minimum security prisoners.
- Educational attainment: prisoners who had completed part secondary education without pursuing further qualifications were more likely to reoffend compared to prisoners who had completed secondary schooling or who had pursued some sort of post-secondary qualification (e.g. tertiary education or an apprenticeship).
- Substance use risk rating: prisoners who were classified as high or highest risk on the substance use offender treatment checklist were more likely to reoffend compared to prisoners who were either low or moderate risk, or who did not complete the checklist.
- Treatment program completion: prisoners who completed at least one treatment program prior to release were more likely to reoffend compared to prisoners who did not complete a treatment program.
A number of factors did not appear to be significantly associated with recidivism. They included:
- Mental illness.
- Intellectual disability
- Violent offending risk rating (those rated a high or highest risk of violent reoffending were no more likely to re-offend than other prisoner groups).
Sex offender risk ratings also proved interesting: prisoners classified as high risk on the sex offender checklist were actually less likely to reoffend than other prisoner groups. Prisoners classified as highest risk were no more likely to reoffend compared to other prisoner groups.
Of the factors associated with recidivism, the three strongest relationships were with age, prior prison admissions, and problematic substance use. Over half of sentenced prisoners released in 2008/09 and 2009/10 were identified as having highly problematic substance use. These findings along with the findings that males, Aboriginal prisoners, and prisoners with low educational attainment were more likely to reoffend, corresponds with national and international research.
The analysis found that prisoners who completed a treatment program had an increased likelihood of returning to prison. This is not supported by national and international research.