The Spy Who Was Innocent

Almost everyone who works with detection technology—whether meant for tracing disease inside the human body or for detecting explosives at an airport terminal—must contend with the pesky nuisance of false positives. What shows up as a cancerous tumor in a diagnostic scan turns out, upon closer examination, to be a benign lump. The mysterious object that looks like a weapon under an airport scanner proves to be a hair dryer. A certain number of such erroneous detections is the unavoidable price of any screening process.