Risk Management - Standard Process/Definitions: Impact/Severity

Critical (C) - An event that, if it occurred, would cause program failure (inability to achieve minimum acceptable requirements).
Serious (S) - An event that, if it occurred, would cause major cost and schedule increases. Secondary requirements may not be achieved.
Moderate (Mo) - An event that, if it occurred, would cause moderate cost and schedule increases, but important requirements would still be met.
Minor (Mi) - An event that, if it occurred, would cause only a small cost and schedule increase. Requirements would still be achieved.
Negligible (N) - An event that, if it occurred, would have no effect on program.

Reference: Risk Matrix User's Guide, Version 2.2, by Pamela E. Engert and Zachary F. Lansdowne, Mitre Document MP99B0000029, November 1999, The MITRE Corporation

Operational Risk Management Severity

Catastrophic - Complete mission failure, death, or loss of system.
Critical - Major mission degradation, severe injury, occupational illness or major system damage.
Moderate - Minor mission degradation, injury, minor occupational illness, or minor system damage.
Negligible - Less than minor mission degradation, injury, occupational illness, or minor system damage.

Reference: Pocket Guide to Operational Risk Management

Other Impact Definitions

Rating	Definition	Equivalent Numerical Value
Severe:	An event whose occurrence will impact the project's cost (and/or schedule) so severely that the project will be terminated.	1

High:	An event that, if it occurs, will cause significant cost (and/or schedule) increases (e.g., increases of more than 5 percent) on the project.	Defaults: 0.65, 0.83, 0.95 Range: 0.65 < Allowable Value < 1

Moderate:	An event that, if it occurs, will cause noticeable cost (and/or schedule) increases (e.g., increases of not more than 5 percent) on the project.	Defaults: 0.35, 0.50, 0.60 Range: 0.35 < Allowable Value < 0.65

Low:	An event that, if it occurs, will cause small cost (and/or schedule) increases that, in most cases, can be absorbed by the project.	Defaults: 0.05, 0.18, 0.30 Range: 0 < Allowable Value < 0.35

None:	An event that, if it occurs, will cause no impact to cost (and/or schedule) of the project.	0

Reference: Garvey, Paul R., "Implementing a Risk Management Process for a Large Scale Information System Upgrade - A Case Study", INCOSE Insight, May 2001, p.5.