The physical protection system (PPS) at a nuclear facility consists of a range of nuclear security measures involving personnel, procedures and equipment. Ensuring that the PPS is operating as designed is crucial for the security of the nuclear material and of the facility itself. An evaluation of the individual elements of a facility's PPS, as well as the system as a whole, provides a measure of the system's effectiveness. This publication provides technical guidance for Member States, competent authorities and operators on evaluating the effectiveness of such systems to protect nuclear material in use and in storage against unauthorized removal, and to protect nuclear material and facilities against sabotage.