Risk criteria represent significant possible events that can cause setbacks or have negative impacts on a given event or activity. They are used in a risk assessment processes to determine what steps can be taken to prepare for, or in the event, of the risks occurring.
These criteria are used with definitions of the different level of impact and likelihood of an event occurring. Impact is used to determine the severity of a problem – such as whether it, for example, causes a delay, injures or death. Likelihood refers to how probable (or likely) a given problem or event is. These definitions are used when assessing risk by assigning a level to each. An impact can be negligible, minor, moderate, major or catastrophic. The likelihood of something occurring can be rare, unlikely, possible, likely or almost certain. These two measures in tandem are used to determine risk.