Today, I'm presenting a guest post from Behailu Bekera, a first-year EMSE PhD student working in the SEED Group. He is studying the relationship between risk-based and resilience-based approaches to systems analysis.
Resilience is defined as the capability of a system with specific characteristics before, during and after a disruption to absorb the disruption, recover to an acceptable level of performance, and sustain that level for an acceptable period of time. Resilience is an emerging approach towards safety. Conventional risk assessment methods are typically used to determine the negative consequences of potential undesired events, understand the nature of and to reduce the level of risk involved. In contrast, the resilience approach emphasizes on anticipation of potential disruptions, giving appropriate attention to perceived danger and establishing response behaviors aimed at either building the capacity to withstand the disruption or recover as quickly as possible after an impact. Anticipation refers to the ability of a system to know what to expect and prepare itself accordingly in order to effectively withstand disruptions. The ability to detect the signals of an imminent disruption is captured by the attentive property of resilience. Once the impact takes place, the system must know how to efficiently respond with the aim of quick rebound.
Safety, as we know it traditionally, is usually considered as something a system or an organization possesses as evidenced by the measurements of failure probability, risk and so on. Concerning the new approach, Hollnagel and Woods argue that safety is something an organization or a system does. Seen from a resilience point of view, safety is a characteristic of how a system performs in the face of disruptions, how it can absorb or dampen the impacts or how it can quickly reinstate itself after suffering perturbation.
Resilience may allow for a more proactive approach for handling risk. It puts the system on a path of continuous performance evaluation to ensure safety at all times. Resilient systems will be flexible enough to accommodate different safety issues in multiple dimensions that may arise and also robust enough to maintain acceptable performance.