Drug busts have been mistakenly double-counted for the past seven years, and some experts warn the exaggerated data might have been used to justify crackdowns on drug users and support bad policy.
NSW Bureau of Crime Statistics and Research BOCSAR director Dr Don Weatherburn admitted his bureau was at fault, and said the drug bust mistakes built gradually from 2010.
Cocaine and ecstasy possession reports to police were inflated more than 30 per cent in recent years, while last year in total, 13,350 recorded drug use/possess events never happened.
“When we saw they [NSW Police] were doing searches and they were proving positive [drug detection] we just assumed they hadn't recorded that positive result, so we added it in ourselves. That was a mistake because they were adding it in,” Dr Weatherburn said.
“It is a large number, but the crucial issue is the trend with drug offences, I'm not saying this is not a bad mistake, but it doesn't seem to have affected the trend [in drug use reports] from March 2012 to March 2018.
“Between 2010 and 2011, however, BOCSAR did release crime trends suggesting that trends in recorded drug possess/use offences were worse than was the case."
Western Sydney University Associate Professor of Criminology Dr Michael Salter said the BOCSAR figures are what policy and policing decisions are based on.
"What role have these inflated statistics had on informing drug policing and law enforcement?" Dr Salter said. "[This] dramatic overestimation of drug detection may have led to a perception of a drug crisis.
"We have seen quite aggressive use of drug detection dogs, and policing at music festivals but to what extent have those tactics been launched to false data?"
Australian drug law reform foundation president Dr Alex Wodak said NSW drug policy had moved in the opposite direction to evidence or ignored it, for more than 30 years.
"Increasing drug use statistics are often used to justify crackdowns [on drug users], which are often introduced for political reasons rather than on the basis of evidence," Dr Wodak said.
"The statistics on drug use going up or down has remarkably little impact on drug policy and we just keep on doing what we're doing," Dr Wodak said. "Sadly, evidence and drug policy often contradict each other, and that's been increasing recently.
Dr Wodak said refusing to allow pill testing at music festivals is based on "spurious nonsense" that may be partly justified by inflated drug use data.
"Where else do we say that ignorance of what you are "taking is a safety measure?" he said.
However, adjunct professor of law and criminal justice at the University of South Australia, Professor Rick Sarre, said crime data rarely drives policy.
"In my 30 years of looking at crime stats, I have rarely seen governments use the stats to do anything more than reinforce a particular focus that they had already been planning," Professor Sarre said. "I am not too fussed and nor should anyone else be that BOCSAR figures might be slightly out from time to time."
Where else do we say that ignorance of what you are taking is a safety measure?Dr Alex Wodak, Australian drug law reform foundation president
NSW Attorney-General Mark Speakman said BOCSAR has a reputation for high-quality reports.
"Its director Dr Don Weatherburn has assured me incidents of this kind have been extremely rare in the 30 years he has been in the position," Mr Speakman said.
"The community should be comforted to know drug possession offences are lower than BOCSAR had initially reported. The government does not apologise for taking a tough stance on illegal drugs."
NSW Greens MLC David Shoebridge said it was "remarkable" that the police didn’t have any internal mechanisms to pick up the over-reporting by BOCSAR.
“Year on year police have demanded additional resources to meet perceived crime levels with much of this perception based on data produced by BOCSAR," Mr Shoebridge said.
“The war on drugs has never been winnable, and what we see from these recent numbers is that the NSW Police is having an even smaller impact on drug supply than many thought."