NIST Interagency Report (IR) 7874, Guidelines for Access Control System Evaluation Metrics, has been released as final. This report provides Federal agencies with background information on access control (AC) properties, and to help access control experts improve their evaluation of the highest security AC systems by discussing the administration, enforcement, performance, and support properties of AC mechanisms that are embedded in each AC system. This document extends the information in NIST IR 7316, Assessment of Access Control Systems, which demonstrates the fundamental concepts of policy, models, and mechanisms of AC systems.