TBD

Abstract

I have noticed that industries “new” to the concepts of system safety seem to have trouble understanding the implications and meaning of the risk assessments that are performed as part of a system safety analysis. For us old hands in the profession, these concepts are second nature and, therefore, we tend not to discuss them. I think that maybe it is worth revisiting these basic concepts from time to time. Who knows, maybe we (I) have been off base for all these years, and we might all learn something new from a discussion.

The basic definition of risk — a combination of the severity of a mishap and the probability that the mishap will occur — seems clear, especially when combined with the definition of a “mishap” as “an event or series of events resulting in unintentional death, injury, occupational illness, damage to or loss of equipment or property, or damage to the environment” (as defined in MIL-STD-882E).

Apparently, risk also has something to do with unintended negative impacts, the severity of those impacts and the likelihood that these negative impacts will occur. This is pretty close to an everyday use of the term. It is not quite as obvious as it looks, however, when attempting to assign a risk to an identified bad outcome.