Developing risk and safety management methods for complex socio-technical systems: from Newtonian reasoning to Resilience Engineering

The nature of work in modern societies calls for a reconsideration of the notion of risk and safety. Technology terribly evolved to deal with fast-moving competitive systemic requirements. The subsequent dynamic interactions among technical, human, procedural and organizational aspects of work contribute to increase the inherent complexity of technological systems, which become symbiotically interrelated to human components. This thesis adopts a design research perspective to develop methods for risk and safety management in complex socio-technical systems, abandoning the Newtonian notion of bimodality and individual failure, in favour of systemic and holistic analyses in line with Resilience Engineering. The research focuses on understanding how systems behave in an ever-changing hardly predictable work environment, not limiting the analysis to fragments of behaviour, i.e. errors. The thesis introduces a Newtonian-oriented method for assessing safety levels. The limitations of this method motivates the exploration of the concept of adaptation and resilience, and thus the field of Resilience Engineering. Combined with a literature review of the research field of Resilience Engineering, the thesis suggests two resilience-oriented methods. The first method adopts a holistic top-down perspective to propose a semi-quantitative framework for analysing systems’ resilient potential. The second method - oriented to local analysis of work domains - aims at exploring functional properties of a system through a multi-layer semi-quantitative framework in order to analyse inter-related patterns of events, rather than simple causal sequences. In sum, this thesis adds methodological contributions to the field of risk and safety management through structured analyses of socio-technical systems. The thesis has a publication-based structure, including a design-oriented summary of the abstract artefacts developed, i.e. the methods, which have been extensively discussed in the appended eleven papers, all published in international peer-reviewed journals.