The purpose of ISO/IEC TR 20000-4:2010 is to facilitate the development of a process assessment model according to ISO/IEC 15504 process assessment principles. ISO/IEC 15504-1 describes the concepts and terminology used for process assessment. ISO/IEC 15504-2 describes the requirements for the conduct of an assessment and a measurement scale for assessing process capability. The process reference model provided in ISO/IEC TR 20000-4:2010 is a logical representation of the elements of the processes within service management that can be performed at a basic level. Using the reference model in a practical application might require additional elements suited to the environment and circumstances. The process reference model specified in ISO/IEC TR 20000-4:2010 describes at an abstract level the processes including the general service management system processes implied by ISO/IEC 20000-1. Each process of this process reference model is described in terms of a purpose and outcomes. The process reference model does not attempt to place the processes in any specific environment nor does it predetermine any level of process capability required to achieve the ISO/IEC 20000-1 requirements. The process reference model is not intended to be used for a conformity assessment audit or process implementation reference guide. Any organization can define processes with additional elements in order to suit it to its specific environment and circumstances. The purpose and outcomes described in ISO/IEC TR 20000-4:2010 are, however, considered to be the minimum necessary to meet ISO/IEC 20000-1 requirements. Some processes address general strategic aspects of an organization. These processes have been identified in order to give coverage to all the requirements of ISO/IEC 20000-1. The process reference model does not provide the evidence required by ISO/IEC 20000-1. The process reference model does not specify the interfaces between the processes.