Final answer:
The hierarchy of project elements is known as a WBS Code (Work Breakdown Structure Code), a tool used in project management to organize and track progress.
Step-by-step explanation:
The representation of the outline hierarchy of a project that can include a combination of letters and numbers is known as the WBS Code (Work Breakdown Structure Code). It is used to uniquely identify each element within the project hierarchy, helping to track project progress and facilitate communication among team members. A WBS Code provides an organized approach by breaking down a project into manageable sections. Creating a skeletal version of your project's WBS can be facilitated by the use of graphic organizers, which allow you to gather and organize initial thoughts and processes associated with each component of the project. During the development phase, it is often beneficial to annotate a graphic representation with brief descriptions of each process to ensure clarity and comprehensive understanding.