Work breakdown structure
[5] WBS is a hierarchical and incremental decomposition of the project into deliverables (from major ones such as phases to the smallest ones, sometimes known as work packages).
It is a tree structure, which shows a subdivision of effort required to achieve an objective, for example, a program, project, and contract.
[12] The concept of work breakdown structure was developed with the Program Evaluation and Review Technique (PERT) by the United States Department of Defense (DoD).
[14] By June 1962, DoD, NASA, and the aerospace industry published a document for the PERT/COST system, which described the WBS approach.
The version history and current revision of the standard are posted on the Defense Logistics Agency (DLA) ASSIST web site.
[19] It has been defined as follows: Mutually exclusive: In addition to the 100% rule, there must be no overlap in scope definition between different elements of a work breakdown structure.
This also ensures that the WBS is not overly prescriptive of methods, allowing for greater ingenuity and creative thinking on the part of the project participants.
When a project provides professional services, a common technique is to capture all planned deliverables to create a deliverable-oriented WBS.
According to the Project Management Institute, the WBS dictionary is defined as a "document that provides detailed deliverable, activity, and scheduling information about each component in the work breakdown structure."
The purpose of the numbering is to provide a consistent approach to identifying and managing the WBS across like systems regardless of vendor or service.
[citation needed] It is a preferred practice that the Statement of work or other contract descriptive include the same section terms and hierarchical structure as the WBS.
For example, shipbuilding for the U.S. Navy must respect that the nautical terms and their hierarchy structure put into MIL-STD[29] are embedded in Naval Architecture[30] and that matching Navy offices and procedures have been built to match this naval architecture structure, so any significant change of WBS element numbering or naming in the hierarchy would be unacceptable.
At WBS Level 1 it shows 100 units of work as the total scope of a project to design and build a custom bicycle.
The number of units allocated to each element of work can be based on effort or cost; it is not an estimate of task duration.
This collaborative technique builds greater insight into scope definitions, underlying assumptions, and consensus regarding the level of granularity required to manage the projects.
