Work Breakdown Structure

It is beyond any reasonable doubt that the Work Breakdown Structure (WBS) is an exceptionally useful tool for planning, estimating, scheduling and controlling any kind of project. The term WBS describes the procedure of subdivision of the project deliverables and workload into smaller more manageable segments. More specifically, “The WBS is a hierarchical decomposition of the total scope of work to be carried out by the project team to accomplish the project objectives and create the required deliverables.” (PMBOK® Guide-Fifth Edition, 2013, p. 126)

The purpose of this wiki-article is not only to thoroughly describe the capabilities and restrains of this method but also to provide guidance to project managers concerning the techniques that can be used for the effective implementation of project Work Breakdown Structures.

Big Idea

Historical Retrospection

The initial forms οf the Work Breakdown Structure (WBS) were developed by the U.S. Department of Defence (DoD) and the National Aeronautics and Space Administration (NASA) at the mid-1960s with a view to regulating projects which had the ultimate goal of enhancing military and space systems respectively. Moreover, the management of these projects was undertaken by a central administration office and many different industrial contractors were recruited in order to contribute to the accomplishment of the huge variety of tasks. So, the WBS tool was used to “…ensure that the total project is fully planned and that all derivative plans contribute directly to the desired objectives” (NASA, 1962). After two decades; namely in 1987 the Project Management Institute introduced the Project Management Book of Knowledge (PMBOK) which provided the necessary guidance on how work breakdown structures could be applied in any kind of project.

Work Breakdown Structure Definition

The WBS process is characterized by the disintegration of the project into separate segments with the aim of managing it in a more efficient and effective way. Furthermore, this practical tool facilitates many other project management procedures like scheduling, efficient resource allocation, monitoring and control of the project. Also, the Work Breakdown Structure provides a complete and clear view of the project scope and deliverables. In addition, it presents with clarity the total workload as determined by the scope statement of the project and analyzes the planned work at the lower levels, also known as work packages. With the help of work packages, the activities that contribute to the planning, assessment, supervision, and control of operations are grouped together.

Work Breakdown Structure Framework

The Work Breakdown Structure (WBS) consists of several layers and which are grouped at the upper and lower levels. Below the composition of a typical WBS is described. To begin with, the content of the WBS levels may vary depending on the type of project and the industry involved. More generally, the main areas of the project are included at these levels. Then we have the lower WBS elements which mainly focus on supporting specific project management processes such as schedule development, cost estimation, resource allocation and risk assessment. These levels are called Work Packages. The official definition of the Work Package is, “A deliverable or project work component at the lowest level of each branch of the work breakdown structure. The work package includes the schedule activities and schedule milestones required to complete the work package deliverable or the project work component.” (PMBOK® Guide-Third Edition, 2004, p.380). Finalizing WBS is done by assigning each work package to a control account and creating a separate identifier for that work package. With the help of these identifiers, the hierarchical summation of the cost, schedule and resources is achieved. “A control account is a management control point where scope, budget, actual cost, and schedule are integrated and compared to the earned value for performance measurement.” (PMBOK® Guide-Fifth Edition, 2013, p.132). Each control account typically involves one or more work packages while each work package cannot be linked to more than one control account. Additionally, these management control points are associated with more than one planning package, which is part of the WBS under the control account with given work content but without specified detailed activities.

Work Breakdown Key Features

Some of the most important prerequisites for qualifying a WBS as high quality and successful are listed below:

• A key feature of WBS is that it is deliverable oriented. In particular, a deliverable is defined as “Any unique and verifiable product, result or ability to perform a service that must be produced to complete a process, phase or project” (PMBOK® Guide-Third Edition, 2004, p.358). Therefore, the WBS should be aligned with the individual deliverables.
• A functional WBS is a hierarchical decomposition of the work. Decomposition is “a planning technique that subdivides the project scope and project deliverables into smaller more manageable components until the project work associated with accomplishing the project scope and providing the deliverables is defined in sufficient detail to support executing, monitoring, and controlling the work.” (PMBOK® Guide-Third Edition, 2004, p.358). In this way, a clear definition of the project scope is achieved with the use of independent sub-deliverables.
• An effective WBS manages to share the project scope with all the stakeholders.
• The work packages it contains should clearly identify the tasks that need to be performed with a view to delivering the work package deliverables.
• Another important prerequisite is the participation of experienced subject experts (SMEs) as well as skillful financial and business managers in its construction.
• It should follow a common course with the development of the project scope until the final definition of the scope.
• The WBS must be open to continuous improvements that may be needed after setting the project scope. .

Application

A number of methods and tools can be employed to create a WBS including outlines, organizational charts, fishbone diagrams, brainstorming techniques, and top-down and bottom-up development strategies. Moreover, WBS templates, as well as corporate guidelines or standards can be referenced or copied for quick-starting WBS development.

Creating WBS: Tools and Techniques

Decomposition

Decomposition is a technique used for dividing and subdividing the project scope and project deliverables into smaller, more manageable parts, the work packages. The level of decomposition is often guided by the degree of control needed to effectively manage the project. The level of detail for work packages will vary with the size and complexity of the project. Decomposition of the total project work into work packages generally involves the following activities:

• Identifying and analyzing the deliverables and related work.
• Structuring and analyzing the WBS.
• Decomposing the upper WBS levels into lower-level detailed components.
• Developing and assigning identification codes to the WBS components.
• Verifying that the degree of decomposition of the deliverables is appropriate.

Expert Judgment

Expert judgement is often used to analyze the information needed to decompose the project deliverables down into smaller component parts in order to create an effective WBS. Such judgment and expertise is applied to technical details of the project's scope and used to reconcile differences in opinion on how to best break down the overall scope of the project. This level of expertise is provided by any group or individual with relevant training, knowledge, or experience with similar projects or business areas. Expert judgment can also come in the form of predefined templates that provide guidance on how to effectively break down common deliverables. Such templates may be industry or discipline-specific or may come from experience gained in similar projects. The project manager, in collaboration with the project team, then determines the final decomposition of the project scope into the discrete work packages that will be used to effectively manage the work of the project.

Top-Down Method

The following steps describe the general top-down process for developing a WBS:

• Step 1. Identify the final products of the project-what must be delivered to achieve project success. A thorough review of high-level project scope documents (such as Statement of Work and Technical Requirements) is recommended to ensure consistency between the WBS and the project requirements.
• Step 2. Define the project’s major deliverables, which are often interim deliverables necessary for the project, but which in themselves do not satisfy a business need (such as a design specification).
• Step 3. Decompose major deliverables to a level of detail appropriate for management and integrated control. These WBS elements are normally tied to clear and discrete identification of stand-alone deliverable products. The sum of the elements at each level should represent 100% of the work in the element above it. Each work package of the WBS should contain only one deliverable.
• Step 4. Review and refine the WBS until project stakeholders agree that project can be successfully completed, and the execution and control will successfully produce the desired deliverables and results.

Bottom-Up Method

The following steps describe the general bottom-up process for developing a WBS:

• Step 1. Identify all the deliverables (or work packages) involved in the project. If participants propose activities, then the associated deliverables, but not the activities, should be included (i.e., translate suggested activities into associated deliverables). This will encompass the entire output of the effort. Each work package should contain only one deliverable.
• Step 2. Logically group related work packages (or deliverables) together.
• Step 3. Aggregate deliverables to the next level, for instance, the parent level. The sum of the elements at each level should represent 100% of the work below it.
• Step 4. Once given group of related tasks has been aggregated to a parent, analyze the subset again to ensure that all the work has been encompassed.
• Step 5. Repeat until all subelements have been aggregated to a single parent representing the project. Ensure that the completed structure includes the whole project scope.
• Step 6. Review and refine the WBS until project stakeholders agree that project planning can be successfully completed, and that execution and control will successfully produce the desired deliverables and results.

WBS (Organizasional) Standards

An organizational WBS standard is a set of principles for constructing a WBS and might include a format, numbering scheme, naming convention, or required elements. WBS standards are common in many organizations with a high level of project management maturity. These standards help ensure consistency and completeness in WBSs throughout the organization. Examples of WBS standards include the following:

• Project management must be a Level 2 WBS element.
• Graphical and textual WBS views must be developed and maintained.

WBS Templates

A WBS template is a sample WBS, with hierarchical elements filled into some level of detail, or a generic WBS “container” that is customized with project-specific information and different life cycles. An organization can have templates for different types of project and different life cycles. The use of WBS standards and WBS templates help promote consistency through reuse of WBSs or WBS components. When reusing existing components, be sure to customize the WBS to the specific need and requirements of the project. Any non-required work or deliverables should be removed so that the WBS is aligned with the project scope.

The use of the WBS standards and WBS templates differs from top-down and bottom-up methodology in that top-down and bottom-up are methods of creating new WBSs, while standards and templates involve the reuse of existing WBS materials.

Annotated Bibliography

Dr Parviz F. Rad, PE CCE. “Advocating a Deliverable-Oriented Work Breakdown Structure”, Cost Engineering - December 31, 1999.

Annotation: This article presents the rationale and methods for modifying the traditional breakdown structure philosophy in order to obtain a WBS that is focused on deliverables.

Project Management Institute. “A Guide to the Project Management Body of Knowledge (PMBOK® Guide)”- Fifth Edition, 2013.

Annotation: This book provides guidelines for managing individual projects and defines project management related concepts. It also describes the project management life cycle and its related processes, as well as the project life cycle.

Eric S. Norman, Shelly A. Brotherton, Robert T. Fried. “Work Breakdown Structures: The Foundation for Project Management Excellence”- John Wiley & Sons, 2008.

Annotation: This book is intended to be a beginning step in filling the information gap that exists between what is currently written about Work Breakdown Structures and what the authors have learned is needed by program and project managers today.

Project Management Institute. “Practice Standard for Work Breakdown Structures”- Second Edition, 2011.

Annotation: This book provides guidance in the initial generation, subsequent development, and application of the WBS. It also includes information derived from accepted project management industry sources.