Theoretical foundations for building organizational safety models for PRA applications

The primary purpose of this paper is to provide a theoretical perspective for extending Probabilistic Risk Analysis (PRA) modeling frameworks to include the effects of organizational factors as the deeper, and sometimes more fundamental causes of accidents and incidents. Vast majority of the quantitative methods and a number of qualitative approaches for assessing the impact of organizational factors on technical systems risk have been developed in the nuclear industry. However in the absence of a comprehensive set of principles and modeling guidelines rooted in theory and empirical studies, all proposed models look equally good, or equally poor, with very little basis to discriminate and build confidence. Therefore, through a multidisciplinary effort, the authors focused on the possibility of improving the theoretical foundations and introduction of a set of modeling principles for the field of Organizational Safety Risk Analysis. Then, as a realization of aforementioned modeling principles, an organizational safety risk framework, named Socio-technical Risk Analysis (SoTeRiA) ^* was developed. The proposed safety risk framework builds a theoretical relation between technical system risk, organizational safety culture, organizational safety structure and practices, and organizational safety climate. SoTeRiA explicitly recognizes the relationships among constructs at multiple levels of analysis, and extend the PRA framework to include the effects of organizational factors in a more comprehensive and defensible way.