Flutterby™! : False positives and police dogs

Las Vegas Review-Journal: Legal challenge questions reliability of police dogs, reports on a lawsuit in Nevada over a U.C. Davis study testing the false positive rates of drugs and explosives sniffing in police dogs, in which a run without any samples was tested:

But of 144 runs, that happened only 21 times, for a failure rate of 85 percent.

Although drug-sniffing dogs are supposed to find drugs on their own, the researchers concluded that they were influenced by their handlers, and that's what led to such a high failure rate.