In airport security scanning, ultra-rare items are harder to catch

A screenshot from the Airport Scanner app.

Eurekalert

In a simulation of airport luggage scanning, a team of researchers has found that the rarer an item is, the less likely a scanner operator is to spot it—that is, if fewer people come through with bomb materials or guns, it will be harder for the operator to spot them when they do.

The Duke University scientists set up the simulation in an “Airport Scanner” app where participants would check virtual suitcases for a set of 78 verboten items, like a stick of dynamite or a gun. Thirty of the items were “ultra rare,” appearing less than 0.15 percent of the time.

Drawing upon 20 million searches, the team found that these ultra-rare items were more difficult for participants to spot than more common things. The ultra-rare items were spotted only 27 percent of the time, while items that cropped up in one percent of suitcases were correctly spotted 92 percent of the time.