Benefits of Decision Support Systems in Relation to Task Difficulty in Airport Security X-Ray Screening

Automated explosive detection systems for cabin baggage screening (EDSCB) highlight areas in X-ray images of passenger bags that could contain explosive material. Several countries have implemented EDSCB so that passengers can leave personal electronic devices in their cabin baggage. This increases checkpoint efficiency, but also task difficulty for screeners. We used this case to investigate whether the benefits of decision support systems depend on task difficulty. 100 professional screeners conducted a simulated baggage screening task. They had to detect prohibited articles built into personal electronic devices that were screened either separately (low task difficulty) or inside baggage (high task difficulty). Results showed that EDSCB increased the detection of bombs built into personal electronic devices when screened separately. When electronics were left inside the baggage, operators ignored many EDSCB alarms, and many bombs were missed. Moreover, screeners missed most unalarmed explosives because they over-relied on the EDSCB's judgment. We recommend that when EDSCB indicates that the bag might contain an explosive, baggage should always be examined further in a secondary search using explosive trace detection, manual opening of bags and other means.