The Work Breakdown Structure (WBS) is a deliverables-oriented, graphical, hierarchical representation of the work required to fulfill the project scope statement.
It is somewhat like a genealogical family tree for the deliverables and requirements, and it’s one of the most important projects management tools.
A good work breakdown structure is a strong framework for good project management.
The Work Breakdown Structure (WBS) serves several purposes:
- Promotes better overall integration between the project management processes.
- It subdivides the work into manageable components that can be scheduled, estimated, and assigned.
- Through the process of creating and updating the WBS, it helps to identify needed work that might otherwise not have been discovered until later.
- It can be used as a visual communication tool for the customer, stakeholders, and project team.
- WBS is an input to activity definition, cost estimating, cost budgeting, resource planning, and risk management planning.
Steps to Create a Work Breakdown Structure (WBS):
- Identify all the project's deliverables and artifacts. Keep the list textual at this stage rather than graphical.
Level zero of theWBS will be the project.
- Look for any inherent categorization and rearrange the list as necessary to organize it under main categories. Strive hard to find a categorization that is related to the deliverables.
These categories will be the first-level hierarchy of the WBS.
- Don't forget to include project management or other related activities. These are also requirements of the project.
- Decompose the deliverables down into the major activities needed to produce them.
Just as we did in step 2, we might begin seeing a categorization emerge from individual activities that will indicate additional components ("subcomponents") that work packages can be grouped under.
- It's likely we'll find some general dependencies and natural sequencing of activities while we're decomposing.
We'll want to reflect these as best as we can at this stage, but don't get too mired down in these details because dependencies and sequences will be addressed while we're creating the project schedule.
- Continue decomposing until we have a level of work packages that are applicable to our project, and that can be assigned, scheduled, estimated, and managed.
If we’re unable to decompose something to a small enough detail, we may need to insert a planning component or package until we can better define the deliverable.
- Review our list of deliverables, components, and work packages. If the classification and organization aren't clear, regroup until it is.
- Create the graphical WBS from the textual lists. Review it for clarity and visual aesthetics.
Create Work Breakdown Structure (WBS) Process Decomposition
Create Work Breakdown Structure (WBS): Inputs
- Project scope statement
The project scope statement details the measurable goals, objectives, deliverables, and requirements of the project, and what the acceptance criteria of deliverables will be.
It also describes the work required to meet all objectives and deliverables of the project, and it also contains milestones, assumptions, risks, and costs.
The deliverables will be compared to the project scope statement to make sure they comply with it.
- Requirements documentation
The product scope and project objectives are broken down into requirements and described in a collection of requirements documentation that's applicable to the project and requirement type.
Requirements can be documented and described in a number of different levels (executive, summary, and detailed) and in a variety of methods (textually or visually).
- Organizational process assets
Organizational process assets are the source of existing policies, processes, organizational data, and knowledge.
These assets include the entire collection of formal and informal methodologies, policies, procedures, plans, and guidelines, as well as the organization's "knowledge base," which includes historical performance data, labor information, service and maintenance history, issue and defect history, project files, and financial data.
In developing requirements and the project scope, templates, checklists, and lessons learned from previous projects are useful.
Create Work Breakdown Structure (WBS): Tools and Techniques
Decomposition breaks down larger items into manageable components.
For example, in the creation of the WBS, the deliverables are decomposed into work packages. In the case of activity definition, the WBS work packages are decomposed into scheduled activities.
Decomposition of the total project work into work packages generally involves the following activities:
- Identifying and analyzing the deliverables and related work,
- Structuring and organizing 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 work is necessary and sufficient.
Create Work Breakdown Structure (WBS): Outputs
- Work breakdown structure
TWBSis deliverables-oriented, graphical, hierarchical representation of the work required to fulfill the project scope statement.
- WBS dictionary
The WBS dictionary is a companion, supporting document for the WBS, and it includes detailed information about the work packages, including an account identifier, responsibilities, statements of work, and contact information.
- Scope baseline
The scope baseline is the approved project scope statement, WBS, and WBS dictionary. The baseline incorporates all approved changes.
- Project document updates
Defining the WBS and WBS dictionary is likely to uncover additional requirements, so updates any project documents in existence would be needed.
Forms of the WBS Structure
The WBS structure can be created in a number of forms, such as:
- Using phases of the project lifecycle as the first level of decomposition, with the product and project deliverables inserted at the second level.
- Using major deliverables as the first level of decomposition.
- Using subprojects which may be developed by organizations outside the project team, such as contracted work. The seller then develops the supporting contract work breakdown structure as part of the contracted work.
Work Breakdown Structure (WBS) dictionary
The WBS dictionary is a companion document to the work breakdown structure and they nearly always go hand-in-hand.
A dictionary keeps the WBS from becoming visually cluttered, and it provides a document for the details and attributes of the WBS elements.
Dictionary entries and the WBS elements are cross-referenced through a common numbering scheme.
In practice, the WBS dictionary is normally begun at the same time as the work breakdown structure is being created.
Some of the information the WBS dictionary might contain about each component and work package can include:
- Statement of work for the deliverable component.
- Expanded description of the work package, including important tasks or items that shouldn't be overlooked.
- Account codes, general ledger accounts, expense account numbers, labor accounts, or time entry accounts.
- Responsible parties or organization.
- Contact information.
- Quality requirements.
- Additional references to technical specifications or documents.
- Additional breakdowns of scheduled activities or costs.