Level of Effort (LOE) is the general or supportive nature of activities that is defined as having no practicable measurable output or product such as general administrative, coordination, accounting, etc.
Reference Definition by Wikipedia: In project management, level of effort (LOE) is a support-type project activity that must be done to support other work activities or the entire project effort. It usually consists of short amounts of work that must be repeated periodically. Examples of such an activity may be project budget accounting, customer liaison, or oiling machinery during manufacturing.
Related Definitions in the Project: The Project Management
