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Australian police diversion for cannabis offences: Assessing program outcomes and cost effectiveness

Project Members: 
image - Marian Shanahan
Dr Marian Shanahan
Honorary Senior Lecturer
image - Matthew Oreilly
Mr Matthew O'Reilly
Short-Term Employee
Project Main Description: 

Police diversion is one of Australia’s most utilised interventions for drug offenders. Yet fuelled in large part by methodological deficits there remain key gaps in knowledge about the outcomes and the cost-effectiveness of such approaches. For example few studies have successfully obtained a control group of offenders who have not been diverted or have looked at program impacts beyond recidivism. Using a purpose built national online survey this study will evaluate the effectiveness and cost-effectiveness of three different forms of police diversion for cannabis use/possess offenders (cautions, expiation and warnings) versus a traditional criminal justice system (CJS) response.

Project Collaborators: External: 

Dr Tim McSweeney
Institute for Criminal Policy Research, Birkbeck, University of London

  1. To compare outcomes including reported change in cannabis use, recidivism, employment status, and health status for cannabis use/possess offenders who have received one of four criminal justice responses:
    • Cannabis cautions which seek to divert offenders into education and/or treatment programs
    • Cannabis expiation which seeks to divert offenders away from the CJS,
    • Non-drug specific warnings and
    • Non-diversionary response (a criminal charge).
  2. To compare the cost-effectiveness between these alternate forms of police cannabis diversion and the traditional CJS response. 
Design and Method: 

This study used use a purpose built national online survey to evaluate the outcomes and cost-effectiveness. This survey has recruited a sample of over 1000 of cannabis use/possess offenders from across Australia who have been detected by police in the past 3-12 months and either diverted into one of the programs or not-diverted. The results of the survey will be sued to assess outcomes across multiple domains (including but not limited to recidivism), multiple groups (diverted and non-diverted offenders) and costs.


The final report has been submitted to NDLERF.

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