Police diversion for cannabis offences: Assessing outcomes and cost-effectiveness

June 2017
Shanahan. M., Hughes, C. and McSweeney, T. 2017a. Police diversion for cannabis offences: Assessing outcomes and cost-effectiveness. Monograph 66 (Canberra: Australian Institute of Criminology). http://www.ndlerf.gov.au/publications/monographs/monograph-66

Police diversion is one of Australia’s most utilised interventions for minor cannabis offenses. This study assessed the effectiveness and cost effectives of three different approaches to cannabis diversion (cautions, expiations and warnings) compared to the traditional criminal justice system response.

A purpose built on-line survey was completed by a self-selected sample of 998 people across Australia who reported having a recent encounter with police for cannabis use or possession. In addition to details on their encounter with police, data was collected on outcome measures such as cannabis use, recidivism, employment, perceived legitimacy of police, health status and costs. The sample was comprised of 195 people who were charged, 614 who received a caution, 69 who received an expiation and 120 who received a warning. 50 percent of each group consumed cannabis at least daily pre-intervention. There were no statistically significant differences between the groups in terms of cannabis dependence, with the majority (72.6%) of respondents classified as having nil or negligible dependence.

Overall, 16.9 percent were categorised as mildly dependent and 10.8 percent as moderately to severely dependent. Post-intervention, the number of days in which cannabis was used decreased in three of the four groups; there was no change in the expiation group. However, there was no statistically significant difference across groups.

The economic costs of the charge group were six to 15 times higher than the diversion groups. Police diversion appears to be associated with a range of positive social outcomes across multiple domains including less disruptive relationships, fewer employment problems and more positive perceptions of police legitimacy.