Risk-based Classification of Incidents

As the penetration of software into safety-critical systems progresses, accidents and incidents involving software in such systems will inevitably become more frequent. Identifying lessons from these occurrences and applying them to existing and future systems is essential if these incidents are to be prevented in the future. Unfortunately, investigative agencies do not have the resources to fully investigate every incident under their jurisdiction and domains of expertise and thus must prioritize certain undesired events and allocate resources accordingly. In the aviation community, most investigative agencies prioritize undesired events based on the severity of their associated losses, allocating more resources to those involving extensive aircraft damage or injury to passengers. We argue that this scheme is inappropriate because it undervalues incidents whose recurrence could have a high potential for loss while overvaluing fairly straightforward accidents involving accepted risks. We then suggest a new strategy for prioritizing incidents based on the risk arising from incident recurrence.