organization-defined circumstance

A structured placeholder — specifically an **assignment-operation parameter** — embedded in a security or privacy control statement, indicating that the implementing organization must supply a locally determined set of situational conditions under which the control action applies or is modified. It is the variable part of a control or control enhancement that is instantiated by an organization during the tailoring process by either assigning an organization-defined value or selecting a value from a predefined list provided as part of the control or control enhancement. Concretely, the assignment operation allows an organization to assign a specific, organization-defined value to the control or control enhancement — for example, a list of roles to be notified or a value for the frequency of testing — and "circumstances" is simply the type of value the control author has left for the organization to fill in. Organization-defined parameters of this kind are used in SP 800-53 controls to provide flexibility to federal agencies in tailoring controls to support specific organizational missions or business functions and to manage risk.