The claim

In support of their plan to legalise pill testing of party drugs in Victoria, the Greens have taken aim at drug detection canines, declaring:



A screenshot of the claim on the Greens' website. ( Supplied )

"Drug sniffer dogs are incorrect 75 per cent of the time."



Is that correct? RMIT ABC Fact Check investigates.

The verdict



The Greens' claim is close to the mark.



The source of the claim, a review conducted in NSW between 2002 and 2004, showed that in 74 per cent of cases where a sniffer dog indicated the presence of drugs on someone, no drugs were subsequently found.



More recent figures from NSW show no drugs were found in 63 per cent of cases after a sniffer dog indicated their presence; for South Australia it was 82 per cent.



While police suggest the dogs are almost always correct in picking up either the presence of drugs or residual traces of drugs, the stated purpose of sniffer dogs is to detect people in possession of drugs — not traces of drugs that may indicate previous use.



The source of the claim

The claim appeared on a Victorian Greens website advocating pill testing — a harm reduction service in which drug users can get information on the content of illegal drugs, allowing them to make informed choices.



A spokesman for the Victorian Greens told Fact Check in an email that the source of the claim was a 2006 NSW Ombudsman's Review of the Police Powers (Drug Detection Dogs) Act 2001.



Over the Ombudsman review period between February 2002 and February 2004, police drug-detection dogs indicated the presence of drugs on someone 10,211 times, with "almost all of these indications resulting in a search".



However, according to the report, "prohibited drugs were only located in 26 per cent of the searches following an indication".



In other words, in 74 per cent of cases where an indication from a drug dog formed the reasonable suspicion necessary for conducting a search, no drugs were found.

Dogs with jobs

In Victoria, there is no specific legislation covering the use of drug detection dogs by law enforcement authorities, but an information sheet prepared by Victoria Police outlines the rationale for their deployment.



A spokesman for Victoria Police told Fact Check drug detection dogs were used as a tactical tool in the investigation of drug use and trafficking.



"Under the Drugs, Poisons and Controlled Substances Act, police have the power to search for illicit drugs in situations when they form a reasonable suspicion that the person is in possession of drugs," the spokesman said.



"When a dog indicates that a person may be in possession of illicit drugs, this assists police in forming reasonable suspicion."



In NSW, police may carry out "general drug detection" using sniffer dogs in certain authorised places including licensed premises, public transport, and sport and entertainment venues.



As with Victoria, "general drug detection" in NSW relates to the detection of drugs that are in the possession or control of a person.



Can the dogs tell the difference between possession and the residual scent of drugs?

A pie chart from the NSW Ombudsman's report shows drug contact was admitted in 59 per cent of cases where no drugs were found, but this isn't the full story. ( NSW Ombudsman )

Dave Wright, a former NSW Police dog trainer, told Fact Check that drug detection dogs were trained through a process of conditioning to recognise and indicate the odour of prohibited drugs.



Mr Wright, who is now the Director of Training at Dog Force Australia, a private specialist dog training company, explained that the dogs would not be able to tell the difference between a residual scent and a scent from someone in possession of drugs.



"They're incredibly sensitive [to smell]. If someone has been carrying drugs, if they've had contact with drugs, even things like carrying currency that's been sitting with drugs — the dogs will often pick up on that," Mr Wright said.



"The sensitivity of the dog's nose is sometimes some of the problem because they're picking up some of the residual recent contact with the narcotic and they're indicating the presence of that."



More recent figures

A spokeswoman for NSW Greens MP David Shoebridge provided Fact Check with data on drug detection dogs in NSW dating back to 2009, which Mr Shoebridge collected via NSW Parliament.



That data shows that over the past decade, 63 per cent of searches following an indication found no drugs. In 2017, it was 61 per cent; for the first five months of 2018 this was the case in 63 per cent of searches.

Instances in which drug detection dogs did not find any drugs in a search are highlighted in orange.



South Australia is the only other state to make similar data publicly available — drugs were found in just 18 per cent of searches conducted after drug dog indications in the 2017-18 financial year.



Fact Check requested the equivalent data from police in all other states and territories. However, none were able to provide figures.



A different measure of accuracy?

In comments referenced in the 2006 NSW Ombudsman's report (page 49), NSW Police said they believed drug-detection dogs were accurate 70 per cent of the time.



"This figure is obtained by adding the proportion of occasions when a drug is found to the proportion of occasions when no drug is found, yet some explanation is provided as to why the dog might have indicated the person searched," the police said.



In an email, a spokesman for Victoria Police said 85 to 90 per cent of people indicated by drug-detection dogs were either in possession of drugs or admitted to having had recent contact with drugs.



A spokeswoman for the Western Australia Police Force said drug detection dogs had been trained to detect narcotics to a high level of accuracy.



"Any positive indications given by our detection dogs result in either a drug find or confirmed dead scent (a location where drugs have been removed recently and residual odour remains)," she wrote in an emailed response to Fact Check.



Issues with the police measure

In its 2006 review, the NSW Ombudsman took issue with NSW Police's measure of drug dog accuracy.



The review revealed that 21 per cent of people who admitted to having been in contact with drugs claimed to have been in the presence of cannabis smoke only.



However, while NSW Police included this figure when determining their accuracy rate, they did not accept the proximity to other drug users as a possible explanation for a dog indicating the presence of drugs on someone.



Other admissions by people of previous contact with drugs were so remote — days, months and even years prior — that they could not reasonably explain an indication by a sniffer dog.



Dr Peta Malins, a lecturer in criminology and justice studies at RMIT University, told Fact Check that including admissions of previous contact with drugs in measuring the accuracy of sniffer dogs was problematic.



"My anecdotal experience is that people will say whatever they think is going to get them out of that situation as quickly as possible," she said.

"If they think it will stop the police strip searching them or doing a more thorough search they may say they were using drugs earlier in the day.



"It's hard to know how accurate these admissions are."



Are the dogs "incorrect"?

Dr Malins said that while there may be no drugs found after an indication, that did not mean the dogs were not picking up on a residual drug odour.



"We can never know for sure if the dog was picking up on a drug that may have been very carefully hidden or whether they may be picking up on traces of a drug that a person may have used or had in their clothes or bag earlier."



Whether or not the dogs were "incorrect" was a definitional question for Dr Malins.

"If police are using a drug dog indication to justify reasonable grounds to search, then you might argue that that's not an accurate enough rate of actually finding drugs to justify being able to search someone on suspicion of possession," she said.



"But the dogs tend to be very accurate in testing environments."



The 2006 NSW Ombudsman report pointed out that the primary objective of using detection dogs was to find people in possession of drugs.



"Although some admissions may support the accuracy of drug detection dogs in picking up the scent of prohibited drugs, this should not be confused with the accuracy of the dogs detecting persons currently in possession of prohibited drugs, which is the purpose for their use."

Principal researcher: Ellen McCutchan

factcheck@rmit.edu.au



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