Standard Terminology
Most service management practitioners will agree that there is an advantage to using a shared and a standard terminology when speaking of how to manage services. To this end, the definitions provided by ITIL® are most often cited. Some terms, however, continue to be used in diverse ways, only adding to the confusion of those who attempt to follow industry standards. This might be due to multiple industry standards, to poetic license, to ignorance or, indeed, to laziness.
The Case of Severity
One such term is severity. Severity is normally used to describe an event or an incident.
However, some practitioners appear to use this term interchangeably with other attributes of events and incidents, such as impact or priority. I propose here a simple way of distinguishing severity from impact, one that is loosely derived from ITIL®.
Events or incidents may be viewed from two perspectives: how do they influence the customers of services and how do they influence the providers of services. We propose that the term impact should describe the influence of an event or incident on the customers, while the term severity should describe its influence on the service provider.