How Accurate Are Drug Sniffing Dogs

Used at airports, train stations and major event, dog sniffing dogs are common. They have been featured on TV and movies and occasionally, at retirement, celebrated in on the media. But how accurate are drug sniffing dogs?

Belgian Malinois have become increasingly popular for narcotics detection tasks, making German Shepherds and Belgian Malinois two of the most popular narcotics detection breeds. Labrador Retrievers, Terriers (e.g., Fox, Welsh, and Jack Russell) and English Springer Spaniels are also used.

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To train a narcotics detection canine, an association must be developed between the canine’s training toy and the odor of controlled substances, usually cocaine, heroin, methamphetamine, and marijuana. When the dog smells the odor of the designated narcotics, it believes it has found its toy. Dogs do not know they are smelling narcotics and not the toy itself. Once this connection between the odor of narcotics and the toy has been implanted in the dog’s memory, it is then taught to perform a certain behavior to signal the handler it has located the odor of what it believes is its toy. This demonstration is commonly referred to as the “alert.”

So how effective are they? It is a mixed bag, and it clear in all studies they aren’t always accurate. Law firms like Keller Law Office in Minnesota claim drug-sniffing dogs are not very accurate. They say multiple studies show alarmingly high error rates, with some results exceeding 50 percent.

A study by Polish researchers from the Department of Animal Behavior at the Institute of Genetics and Animal Breeding of the Polish Academy of Science, found on average, dogs found hidden drugs correctly 87.7% of the time, with false indications happening about 5% of the time, and in 7% of cases, the dogs were unable to find the hidden substances.

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The group found German Shepherds were the top narc dog, while terriers, who are often used due to their small size, were poor performers. Dogs performed better indoors than outdoors, while familiarity with room had no significant impact. Finding drugs outdoors or inside of a car were the most difficult tasks; these drug sniffing dogs were only 58% accurate when searching within a car.

Some drugs can also leave residual odors dogs do not distinguish from the actual presence of substances, with cannabis buds and hashish leaving the strongest after-odors, all dogs signaled the presence of hashish a day after it was removed from the location, and 80% did so after 48 hours.

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In the UK, revealed drug sniffing dogs had incorrectly detected illicit substances on patrons in almost 75% of the 95,000 searches undertaken since 2012. While they are doing a review, the practice continues.

Police dogs and their efficacy is often perceived as highly accurate and nearly infallible which data doesn’t always support. The good new is K9s are also immune from racial and other biases. Enforcement agencies globally rely on their keen sense of smell to find hidden narcotics.

Other opportunities for is in sniffing out explosives, but dog teams alerted to the training sample in both trials (alert rate = 100%), indicating a strong response to the training sample. On average, dog teams alerted to the 30 g subsample of the confiscated explosive in 10 of 14 trials across all dogs at an alert rate of 71.43%.  So still not the best score, but better than average.

The most successful dogs are trained to detect crop pests and diseases. A study by the US Department of Agriculture found these dogs identified trees infected with citrus greening disease with 99% accuracy; they could detect infection as early as two weeks after onset.  Maybe it would be a better use?