Influence of Information Layout on Diagnosis Performance

Effective diagnosis performance is necessary for the operation of safety-critical industrial systems. Diagnosis depends on the information provided, perceived, interpreted, and integrated by operators. This paper examines the influence of information layout on diagnosis performance. Three layouts were designed to meet the information requirements identified through a work domain analysis and task analysis. One interface depicted the vertical means-end relations in the abstraction hierarchy, a second depicted the horizontal relations between nodes, and a third followed a conventional mimic layout. Because vertical means-end relations present a clear mapping between functional and physical information, it was hypothesized that the vertical interface would facilitate more effective use of functional information and thereby better support diagnosis performance compared with the horizontal and mimic interfaces. No significant influence of information layout on diagnosis accuracy or completion time was found. However, the participants who used the vertical and horizontal interfaces were more confident with their diagnosis conclusions than those using the mimic interface. In addition, the participants using the vertically integrated interface spent significantly less time generating correct hypotheses than the participants using either the horizontal or mimic interfaces. These findings stress the importance of information layout for interfaces of safety-critical systems.