The Australian government expends an estimated $1.7 billion on responding to illicit drugs every year, with policing comprising 64% of this expenditure. One core assumption underpinning this investment is that police can deter, discourage or prevent drug offending. It is argued that drug laws and enforcement of those laws will reduce involvement in drug use and trafficking. But, there remains very limited research into the extent or nature of deterrent effects. One cause of this gap is methodological.