Structural roles reflect the structural aspects of relationships between entities. Structural roles describe prerequisites, feasibilities, or competences for acts. [ISO 22600-2] Structural Role is used to illustrate the type of roles that may be used in a privacy policy or Role Based Access Control (RBAC) permission. Structural codes are currently provided by ASTM E1986-09. [HL7 DAM] Note that this role is called a "Session Role" in American National Standards Institute (ANSI) / InterNational Committee for Information Technology Standards (INCITS).