Initiator-bound Access Control Information (ACI) that can be compared with security labels of Resources. Examples of clearance are Normal, Restricted, and Very Restricted. [HL7 PASS SLS] and [HL7 HCS] (Note that there used to be a class called User Role, which has since been merged into this Clearance class. The definition of the User Role Class was: "Specifies the role of a user of a computer system. The role is typically associated with the Information Requester and specifies what capabilities are available to a specific type of computer user (i.e., in the Windows operating system, a user may have the role of Administrator which enables the capability to add new users).")