Structural and functional changes in an Australian high-level drug trafficking network after exposure to supply changes

Dr Matt O’Reilly1, A/Prof Caitlin Hughes2, A/Prof David Bright2, Prof Alison Ritter3

1NSW Police Force, Sydney, Australia, 2Flinders University, Adelaide, Australia, 3UNSW, Syndey, Australia


Illicit drug markets and associated supply changes (including changes in availability and purity) have been studied for many years but with limited attention to how drug trafficking networks adapt to such changes and the consequences thereof: the aim of this study.



A longitudinal social network analysis was applied to a high-level drug trafficking network which supplied methamphetamine and other drugs over 15 years in Melbourne, Australia (1997-2007). Data were extracted from judges’ sentencing comments, a biography, and mainstream media. Five time periods were devised, and supply changes (distinguishing between law-enforcement-caused and non-law-enforcement-caused) were coded in each period. Then, the associated structural and functional changes in the network were analysed within and between periods.



Thirty-two supply changes were identified, of which 59% were law-enforcement-caused and 41% not. Temporally associated structural and functional changes included a shift from mostly international trafficking to mostly domestic manufacture (and vice versa), recruiting corrupted public officials, decentralisation, as well as changes in network density, roles, and size. Despite 32 supply changes, the network continued to sell large quantities of drugs for at least 15 years.



This research highlighted the complex adaptive nature of the illicit drug trade and its resilience to market change. Supply changes were associated with a variety of structural and functional changes in the network, some of which resulted in negative consequences such as corruption or increased domestic manufacture of methamphetamine. This suggests that whenever supply disruptions take place, it is important to be prepared for trafficker adaptations.


Matt began his career in academic research in 2012 after completing a bachelor of psychology. Initially, he provided research assistance in the areas of clinical and forensic psychology. Then in 2014, Matt began work on a doctoral thesis at the National Drug and Alcohol Research Centre in Sydney. This research identified supply changes in Australia’s MDMA and methamphetamine markets, and then examined how high-level drug traffickers adapted to those supply changes. The thesis was completed in 2018, and the research Matt’s presenting on today formed part of that thesis. He is now working as a Policy and Programs Officer for NSW Police Force.

Australia & New Zealand Society of Evidence Based Policing

The Australia & New Zealand Society of Evidence Based Policing (ANZSEBP) was formed in April 2013 in Brisbane, Australia. The ANZSEBP is a police practitioner-led Society. The mission of the ANZSEBP is to develop, disseminate and advocate for police to use scientific research (“the evidence”) to guide best practice in all aspects of policing. The ANZSEBP Chairperson serves on the Executive Board of the British Society of Evidence Based Policing, ensuring that the ANZSEBP works cooperatively with an international group of police to advance evidence based policing.

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