A quantitative measure of fitness for duty and work processes for human reliability analysis

Fitness for duty and work processes have been recognized as important performance shaping factors (PSFs) for human reliability analysis (HRA). However, current HRA methods offer no or limited guidance for determining PSF levels, so analysts have relied on their expert judgment during the selection of such levels. In this study, we propose a practical framework to quantitatively measure the levels of socio-psychological PSFs using human error data, based on plant experiences. This methodology calculates the error occurrence intervals and their moving average for a certain error cause reported in inspection reports. The proposed framework is applied to the HuRAM+ (Human related event Root cause Analysis Method plus) database as a case study. The usefulness and requirements of the proposed framework are then discussed.