A human-machine interface evaluation method: A difficulty evaluation method in information searching (DEMIS)

A human-machine interface (HMI) evaluation method, which is named “difficulty evaluation method in information searching (DEMIS)”, is proposed and demonstrated with an experimental study. The DEMIS is based on a human performance model and two measures of attentional-resource effectiveness in monitoring and detection tasks in nuclear power plants (NPPs). Operator competence and HMI design are modeled to be most significant factors to human performance. One of the two effectiveness measures is fixation-to-importance ratio (FIR) which represents attentional resource (eye fixations) spent on an information source compared to importance of the information source. The other measure is selective attention effectiveness (SAE) which incorporates FIRs for all information sources. The underlying principle of the measures is that the information source should be selectively attended to according to its informational importance. In this study, poor performance in information searching tasks is modeled to be coupled with difficulties caused by poor mental models of operators or/and poor HMI design. Human performance in information searching tasks is evaluated by analyzing the FIR and the SAE. Operator mental models are evaluated by a questionnaire-based method. Then difficulties caused by a poor HMI design are evaluated by a focused interview based on the FIR evaluation and then root causes leading to poor performance are identified in a systematic way.