This term extends the concepts of accident and system failure. Rather than relating to the actual results, which involve random circumstances, it is about the potential results, due to design mistakes. Therefore, it is more useful for resilience assurance.

Definition

An incidence is an instance in which the system operation runs out of the design scope, implying that it gets in an exceptional situation, and hence, its behavior is unexpected.

Classification

Incidences can be classified according to the resulting costs:

• Critical incidence, if it involves a need in the system definition, resulting in an additional development cycle 
• Accident,  if it involves casualties (such as in many airplane crashes), or obvious high costs (such as in the TMI accident)
• Near-miss, if the system situation exits the design scope, and consequently its behavior is unexpected
• Anecdote,  if the costs are hidden (such as lost of operational time or operator's frustration).

Updated on 23 Sep 2016.