Work Break-down Structure

Abstract

Successful project management depends heavily on the ability of project managers to determine the content and scope of project work according to the characteristics of project products (deliverable) and activities. WBS can analyze the project process comprehensively and systematically, and it is also a very effective basic method of project management.

Work breakdown structure (WBS) is a principle of project management that arranges project elements based on the deliverables instead of a schedule activity. which summarizes and defines the whole scope of work of the project, and each descending level represents a more detailed definition of the project work. WBS is always at the center of the planning process, and it is also an important basis for making progress plans, resource requirements, cost budgets, risk management plans, and procurement plans. . WBS is also an important basis for controlling project changes. The key process for building a WBS is to disintegrate the assignments into an amount of light workload and distribute it to every individual who is considered as a participant.

Big ideas

Definition

Work breakdown structure (WBS) is an effective tool in project management and systems engineering which considers deliverables as the key elements of a structure. The structure decomposes the project into different levels and each lower level defines a more detailed project work. The department and staff are divided into groups according to the work packages in WBS.

WBS consist of three key elements. Work is the task that can produce tangible results; breakdown is the hierarchical structure of gradual subdivision and classification; the structure is to organize each part according to a certain pattern.

History

In 1957, the U.S. Navy’s Fleet Ballistic Missile Program occurred a heavy schedule delay. The team tried to solve the problem and developed a form to define tasks and organize activities needed for a project on the basis of deliverables, which became known as PERT (program evaluation and review technique).

Subsequently, the Department of Defense (DOD) and NASA published the first definition of the work breakdown structure process in 1962, then the first official reference in 1968. The Work Breakdown Structures for Defense Materiel Items (MIL-STD-881) became a standard across the DOD, with templates released for specific military applications.

In 1987, the Project Management Institute introduced the work breakdown structures as standard practice to non-military applications. Then the term “work breakdown structure” was officially documented in 1993 for applications in business firms and other organizational projects.

In June 1999, the PMI Standards Program developed the Work Breakdown Structure (WBS) Practice Standard which summarizes the planning process into three critical steps, scope planning, scope definition, and work breakdown structure development.

Content of WBS

WBS should include project products, project organization, and division of project schedule. The structure focus on the work packages of the project which is the deliverables. The accomplishment of the project is based on the coordination and arrangement of all work packages. Therefore, the work packages that are not included in the WBS do not belong to the scope of the project.

WBS dictionary

For WBS, it is necessary to establish a WBS dictionary to describe each work part. WBS dictionary usually includes information such as work package description, schedule date, cost budget, and personnel allocation. The main application of the WBS dictionary is to define the work in detail to help create the product that will be obtained with the execution of the project. Work Packages represent the list of tasks in order to produce the particular unit of work. When WBS and OBS are used together, a coding system should be established. The coding scheme is the coding system used to uniquely determine each unit of the project work breakdown structure. Costs and resources are allocated to this coding structure. Used correctly, the WBS Dictionary becomes much more than a document that describes the work. It becomes a project kaleidoscope that allows you to look at your project data in an infinite number of ways.

WBS elements

In fact, WBS elements are "nodes" in WBS structure. From the form of expression, they are "boxes" in "organizational chart". These boxes represent independent deliverables with the subordinate or superior relationship. After decades of development, most organizations prefer that the WBS structure be necessarily related to the project objectives and must be oriented to the final product or deliverables, so the WBS element is more suitable to describe the composition of the output product. It is obvious that different organizations and cultures use different methods, procedures and resources to complete the same structure work, but their destination must be the same and meet the specified requirements. On the one hand, by considering every WBS element as a unique deliverable can we control and manage the project most effectively. On the other hand, only by identifying the deliverables can we clarify the methods, procedures and resources used by internal or external organizations to complete the work. The lowest level of element in WBS is called work packages.

Work packages

Work package is a unit of work required to fulfill a specific request. Work packages explicitly express the activity that need to be performed corresponding to the specific work, as well as the start and finish dates of the activity. It is the basis of all project work, and also suitable for a status report. The formats include work package assignment table and work package description report. The basic requirement of establishing work package is to provide sufficient and appropriate management information for project control. Work package is the lowest level project deliverable of WBS, which has the following characteristics:

1. Work packages can be assigned to another project manager for planning and execution.

1. The work package can be further decomposed into the WBS elements of the subprojects.

1. Work package can be further decomposed into activities when making project schedule.

1. The work package may be the responsibility of a single department or contractor. When used for subcontracting outside the organization, it is called the commitment package.

1. The definition of work package should consider an 80-hour rule or two-week rule which means the completion time of any work package should not exceed 80 hours. At the end of each 80 hours or less, only the accomplishment of the work package is reported. Through this method of regular inspection, the adjustment of the project could be controlled.

WBS dictionary

• rule of task decomposition

• building requirements

• decomposition scheme