ITIL Change Priority
ITIL Change Priority levels can be defined using a variety of variables. As part of the Change Management process being able to establish the change priority is part of the change evaluation.
ITIL Change Priority levels are typically set at levels such as High, Medium, Low and Urgent or Emergency. These levels are determined by understanding the combined impact and urgency of the change being considered. The impact of a change describes the degree of 'disturbance' that a change may have on the infrastructure or what impact on the business not performing the change may have on the organization.
The urgency of a change is a way of expressing the level of resources that should be applied to the change being considered. Resources can be in the form of people, infrastructure, costs, etc.
The actual definition of High Impact or Medium Urgency will be defined by each organization, based on variables that are important to that business (e.g. financial, safety, compliance with legal requirements, customer satisfaction, speed of response, etc.)