This standard defines the HRL scale and provides the guidance necessary for human systems experts to apply it. This standard uses the term human readiness to refer to the readiness of a technology for use by the intended human users in the specified intended operational environment. Addressing the current physical or mental readiness of human operators who will use the technology in order to accomplish their mission work is outside the scope of this standard. Further, although the HRL scale is applied in the context of existing systems engineering and HSI processes, this standard does not provide a detailed process for conducting HSI assessments. Existing human systems engineering practices, processes, and tools are critical to provide the foundation from which HRL ratings can be derived; however, the purpose of the HRL scale is not to dictate the processes and tools that should be used or how they should be used. This type of information resides in standards such as SAE6906 Standard Practice for Human Systems Integration and in organization-specific HSI handbooks and guidance. For example, SAE6906 provides detailed requirements specifying how to integrate HSI processes within the overall systems engineering approach throughout the system lifecycle.