Socio-Technical Risk Analysis

Our new blog is from Dr. Zahra Mohaghegh of the University of Maryland.  I had the pleasure of meeting Zahra earlier this year at PSAM and learning something of her work. This blog features her paper from that conference; a paper entitled “Development of an Aviation Safety Causal Model Using Socio-Technical Risk Analysis (SoTeRiA)”.  She recently published a new book Socio-Technical Risk Analysis that expands on her doctoral dissertation “On the Theoretical Foundations and Principles of Organizational Safety Risk Analysis”.  My thanks to Zahra for sharing her paper and for providing the context with the following preface:

 “My Ph.D. research has convinced me that the new generation of PRA should include a  more comprehensive coverage of organizational factors since the supporting organization is not only the root cause of human errors, but is also a contributor to hardware and software failures.  

I  realized that, in the absence of a comprehensive theory, or at least a set of principles and modeling guidelines rooted in theory, all existing models (regarding organizational influences on safety/risk) look equally good, or equally poor, with very little basis to discriminate, or determine their reliability. Therefore, as a result of multidisciplinary efforts, I proposed a set of thirteen principles for organizational safety risk analysis in order to create a common vocabulary in this area of research. These principles have been published in detail in a paper in the Safety Science Journal.

The arguments presented in the 13 principles highlight two important challenges for organizational safety risk analysis:  first, we need to move from deviation-based models — for instance, the Swiss-Cheese analogy — to a model that is based on an “organizational performance theory”.  And second, we need to find appropriate techniques to operationalize such a theory in a way that can frame the collective nature of the organization. Overcoming these two challenges was the main focus of my research.

Based on the proposed 13 principles, I developed a safety model and called it SoTeRiA, which stands for Socio-Technical Risk Analysis. The Soteria framework is a theoretical foundation for the integration of both social aspects (such as safety culture) and structural features (such as safety practice) with technical system PRA models. Some existing frameworks only cover safety culture while others only include safety practices. But, none integrates both aspects.  Most of the links in SoTeRiA are supported by organizational and safety literature. In some specific cases, expert judgment was used to fill theoretical gaps. More details on SoTeRiA are published in a paper in the Journal of Safety Science. [Safety Science, Vol. 47, 2009]

Additional contributions of my research relate to the search for appropriate techniques to quantify the SoTeRiA framework. First of all, because of the multidisciplinary nature of organizational safety frameworks, a “single” modeling technique is not adequate, and so we need a “hybrid” integration of different modeling methods.  In my paper, published in the RESS Journal [Reliability Engineering and System Safety, Vol. 94, Issue 5, 2009], I explained in detail how I adapted the appropriate techniques and created a hybrid integration of probabilistic and deterministic approaches to quantify Soteria. I proposed a combination of Bayesian Belief Network (BBN; as a probabilistic technique) and System Dynamics (SD; as a deterministic technique) with the classical PRA techniques for risk analysis.  I used classical PRA techniques (ESD/FT) for the evolution of risk scenario and utilized BBN to model the uncertain nature of the relation between human performance and its organizational context.  SD is used to model the deterministic organizational relations. SD also provides a dynamic integration among the other modules (this means PRA and BBN).

I also applied a simplified version of Soteria in aviation maintenance to show the feasibility of this hybrid technique. ”

To read the full paper, click here:    Zahra M. PSAM Soteria paper_126_1


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