How a Drug and Explosives Detector Proved Useless: Military Use of the GT200

The GT200 device has been extensively used by the Mexican armed forces to remotely detect and identify substances such as drugs and explosives. A double blind experiment was performed to test its efficacy. In seventeen out of twenty attempts, the GT200 failed in the hands of certified operators to find more than 1600 amphetamine pills and four bullets hidden in a randomly chosen cardboard box out of eight identical boxes distributed within a 90 m x 20 m ballroom. This result is compatible with the 1/8 efficacy expected for a useless device, and is incompatible with even a moderately effective working one.