Article summary with The complexity of failure: Implications of complexity theory for safety investigations by Dekker a.o. - 2011

Often when an accident occurs, people tend to point out a single actor that is to blame, even though we live in a complex society and the actual cause is complicated and multifaceted. This research aims to provide a critical note on the traditional philosophical-historical linear take on failure in complex systems. In order to give a more accurate overview of the events leading to an accident, the researchers use the Newtonian analysis of failure, which takes the relationship between cause and effect in account, as well as foreseeability of harm, time-reversibility and the ability to come up with true story about the accident.

What does the Cartesian-Newtonian worldview imply for system safety?

According to the Newtonian science, whether the whole functions or not can be explained by the functioning of the components. According to this way of thinking, the malfunctioning of components is analyzed in order to understand a complex system failure. A complex world is simplified by breaking it down into simple pieces. For example, a human error can be broken down into memory failure, attention failure and perceptual failure. In this theory, there must always be a cause and an effect. When the consequences are big, the actions leading to the cause are blamed more.

This theory is based on the idea that everything can be broken down into matter and movement. Solving an accident becomes a matter of finding the element that is to blame. Foreseeability of harm means that accidents can be predicted when all the details about the state of the parts and their movements are known. Time-reversibility means that any event can be reconstructed, since cause and effect are determined in both the future and the past.

What does complexity worldview imply for system failure?

The limitation of the Newtonian science is that the processes and the combinations of factors that lead to an accident are not taken into account. The combination of factors, different elements being exposed to different influences simultaneously, is called complexity. Complex systems are defined by the interaction of different components. According to this worldview, accidents cannot be explained by breaking down a system into components because of the importance of interactions between them.

One of the characteristics of a complex system is that it has a history that explains the behaviour of the system. This history is large and complicated, and cannot always be reconstructed. This worldview is marked by assymetry and nonlinearity. There is no broken part that can be discovered and explain a big accident. An example of a complex system failure is the high pressure on low-budget airlines. Problems with an airplane were marked as maintenance issues, which later led to a plain crash. The problem is not a malfunctioning part, but rather a structural issue of funds falling short. This worldview implies that events cannot be reconstructed and are irreversible. Events are also not foreseeable anymore, and decision makers have to rely on calculations of probabilities.

In conclusion, viewing accidents as complex means that they can no longer be reconstructed in order to find a single cause. Investigators can however create different narratives, taking the interactions between different factors in account.