Editing Work breakdown structure (section)

== History ==
The concept of work breakdown structure was developed with the [[Program Evaluation and Review Technique]] (PERT) by the [[United States Department of Defense]] (DoD). PERT was introduced by the U.S. Navy in 1957 to support the development of its [[UGM-27 Polaris|Polaris]] missile program.<ref>[http://www.crosstalkonline.org/storage/issue-archives/1998/199807/199807-0-Issue.pdf Fleming, Quentin W., Joel M. Koppelman "Earned Value Project Management" CROSSTALK: The Journal of Defense Software Engineering July 1998, p 20]</ref> While the term "work breakdown structure" was not used, this first implementation of PERT did organize the tasks into product-oriented categories.<ref>Haugan, Gregory T., Effective Work Breakdown Structures, pp7-8</ref>

By June 1962, DoD, [[NASA]], and the aerospace industry published a document for the PERT/COST system, which described the WBS approach.<ref>DOD and NASA Guide, PERT/COST System Design, June 1962</ref> This guide was endorsed by the Secretary of Defense for adoption by all services.<ref>Hamilton, R. L., ''[https://web.archive.org/web/20110604181820/http://handle.dtic.mil/100.2/AD603425 Study of Methods for Evaluation of the PERT/Cost Management System]'', [[MITRE Corporation]], June 1964</ref><!-- Please note that "Defense Materiel Item" is a term of art and not a mis-spelling of "material" --> In 1968, the DoD issued "Work Breakdown Structures for Defense Materiel Items" (MIL-STD-881), a [[United States Military Standard|military standard]] requiring the use of work breakdown structures across the DoD.<ref>MIL-STD-881, 1 November 1968</ref>

The document has been revised several times.  As of May 2023, the most recent revision is F, released 13 May 2022. The version history and current revision of the standard are posted on the Defense Logistics Agency (DLA) ASSIST web site.[https://quicksearch.dla.mil/qsdocdetails.aspx?ident_number=36026]  It includes WBS definitions for specific defense materiel commodity systems and addresses WBS elements that are common to all systems.

Defense Materiel Item categories from MIL-STD-881F are:
*  Aircraft Systems
*  Electronic/Generic Systems
*  Missile/Ordnance Systems  
*  Strategic Missile Systems
*  Sea Systems
*  Space Systems 
*  Ground Vehicle Systems  
*  Unmanned Maritime Systems
*  Launch Vehicle Systems
*  Information Systems/Defense Business Systems

The common elements identified in MIL-STD-881F, Appendix K are: Integration, assembly, test, and checkout; Systems engineering; Program management; System test and evaluation; Data; Peculiar support equipment; Common support equipment; Operational/Site activation; Contractor Logistics Support; Industrial facilities; Initial spares and repair parts. The standard also includes additional common elements unique to Space Systems, Launch Vehicle Systems, and Strategic Missile Systems.

In 1987, the [[Project Management Institute]] (PMI) documented expanding these techniques across non-defense organizations. The ''Project Management Body of Knowledge'' (PMBOK) Guide provides an overview of the WBS concept, while the "Practice Standard for Work Breakdown Structures" is comparable to the DoD standard but is intended for more general application.<ref>Haugan, Gregory T., The Work Breakdown Structure in Government Contracting,  Management Concepts, 2003 {{ISBN|978-1567261202}}</ref>