Why stop after 20 minutes? Breaks and target prevalence in a 60-minute X-ray baggage screening task

• Published in: International journal of industrial ergonomics Vol. 76; p. 102897
• Main Authors: Buser, Daniela, Sterchi, Yanik, Schwaninger, Adrian
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2020; Elsevier BV
• Subjects: Airline security; Airport security; Airports; Baggage; Breaks; Detection measures; Passenger screening; Schedules; Screening; Security; Target detection; Target prevalence effect; Time on task; Visual search; Workloads; X-ray image inspection; X-ray image inspection; Breaks; Detection measures; Visual search; Target prevalence effect; Time on task
• ISSN: 0169-8141; 1872-8219
• DOI: 10.1016/j.ergon.2019.102897

Current EU regulation restricts continuously reviewing X-ray images of passenger baggage to 20-min duration as a precautionary measure to prevent performance decrements in airport security officers (screeners). However, this 20-min limit is not based on clear empirical evidence on how well screeners can sustain their performance over time. Our study tested screeners in a 60-min simulated X-ray cabin baggage screening task. One group took 10-min breaks after 20 min of screening; the other group worked without breaks. We found no decrease in performance over 60 min in either group. Breaks did not affect performance, but they did reduce the amount of subjective distress. By varying target prevalence, we found that da with a slope of about 0.6 is a more valid measure of detection performance than d'. Target prevalence caused a criterion shift. Our results provide a basis for conducting field studies of prolonged screening durations, and open the discussion on whether more flexible break policies and work schedules should be considered. •Screeners maintained their performance over 60 min in a simulated baggage screening task.•Breaks had no effect on screener performance.•Screeners working 60 min without breaks reported more distress.•Detection measure da with a slope of approximately 0.6 was more valid than d'.•Target prevalence caused a criterion shift at the beginning of testing.