Understanding individualistic response patterns when assessing expert operators on nuclear power plant control tasks

We evaluated the performance of three highly practiced participants on three task types that comprised a simulated nuclear power plant control operation. Multiple subjective, physiological, and objective performance measures were collected on these three highly-practiced individuals. Results indicated ceiling effects in terms of performance accuracy, yet each individual adopted a unique response strategy across the respective sub-tasks. Their maximised accuracy was achieved at the expense of longer response times across differing sub-tasks. The measures which proved diagnostic and predictive of performance capacity were explored. The current conclusion presents us with an invidious problem in that performance and workload associations, insensitivities, and dissociations may be unique to each individual operator, and may well depend also upon the overall task in context. Such findings push our science away from seeking nomothetic assertions and toward individuated concerns. In consequence, the age of the idiographic may well be upon us. Practitioner summary: The importance and relevance of nuclear power control is self-evident. Concerns here have centred around the safety of the technology and its operators. Our work informs practitioners in this industry, and in Ergonomics in general, of the response of highly trained individuals in these safety-critical, operational domains. We show that even experts engage in personal and individual strategies, an observation critical to the assessment of this specific workplace, and potentially all others. Abbreviations: NPP: nuclear power plant; ROs: reactor operators; MCR: main control room; LOA: levels of automation; EOP: emergency operating procedure; OP: operating procedures; ISA: instantaneous self-assessment; DSSQ: Dundee stres state questionnaire.