What is the Work Breakdown Structure?
WBS work breakdown structure is the key to any deliverable building project organizing the job of the team into manageable parts. The PMBOK defines the WBS as a “deliverable-oriented hierarchical decomposition of the work to be executed by the project team.” The work WBS defines the scope into manageable work packages that project members can understand, as each level of the WBS provides further definition and detail.
WBS always created by identifying the major functional deliverables & subdividing those deliverables into smaller systems & sub-deliverables. These sub-deliverables are decomposed until a single team member can be assigned. At this WBS level, the specific work packages required to produce the sub- deliverable are identified & grouped together. The work package represents a list of activities to produce a specific unit of work. If you’ve seen detailed time schedules of any project time schedules, then you’ll recognize the activities under the work package as the “stuff” people need to complete at a certain time and within a specific level of effort.
Why use a Work Breakdown Structure In Project Management?
The WBS has many benefits in addition to defining & organizing the project work. The project budget can be allocated to the top WBS levels of the work breakdown structure and department budgets can be calculated quickly based on the WBS work breakdown structure of each project. By allocating time & cost estimates to specific sections of the WBS, a project schedule & budget can be quickly developed. As the project executes, specific sections of the work breakdown structure can be tracked to identify project cost performance and identify issues & problem areas in the project organization.
The project WBS can also be used to identify potential risks in a given project. If the WBS has a branch that is not well defined then it represents a scope definition risk. These project risks should be tracked in a project log & reviewed as the project executes. The project manager can also recognize communication points and formulate a communication plan across the project organization by incorporating the work breakdown structure with an organizational breakdown structure.
Work Breakdown Structure Guidelines
The following guidelines should be considered when creating a WBS:
- Top-level represents the final deliverable or project
- The WBS Sub-deliverable contain work packages that are assigned to an organization’s department or unit
- All elements of the WBS don’t need to be defined to the same level in the WBS
- The WBS Work Package defines the work, duration, and cost of the tasks needed to produce the sub-supply
- In the work breakdown structure, work packages in WBS should not exceed 10 days
- Work packages in WBS should be independent of other work packages in the WBS
- The Work packages in the WBS are unique & should not be duplicated across the WBS.
Characteristics of the Work Breakdown Structure
- Hierarchy: The WBS is of a hierarchical type. — “child” level has a strict hierarchical relationship with the parent level. The sum of all child elements is expected to give you the parent element.
- 100% rule: Every level of decomposition must be 100 percent of the level of the parent. It should also have at least two elements for lower WBS.
- Mutually exclusive: All elements must be mutually exclusive at a given level in a WBS. Neither their deliverables nor their work may overlap. This aims at eliminating miscommunication and duplication of work.
- Outcome-focused: The WBS needs to focus on the outcome of the work, i.e. the results, rather than the activities needed to get there. — aspect should be represented through nouns, not through verbs. This is an immense source of confusion for WBS beginners.
Benefits of a WBS
- Project schedule: The WBS forms the basis for the schedule and budget of the project. When you know all the deliverables and their hierarchical relationships needed to complete the project, assigning resources and setting deadlines would be much simpler.
- Accountability: Since all components in a WBS are mutually exclusive, accountability is supported by this. A team assigned to a single package of work is solely responsible for its completion. That reduces the burden for overlaps.
- Commitment: The WBS provides teams with a very high-level description of their duties. Since each team is responsible for one particular aspect at a time, it helps to make them more committed to completing their assigned tasks.
- Reduces ambiguities: The WBS development process includes the project manager, project management, and all of the related stakeholders. This promotes dialogue and helps lay out their roles for those concerned. So everyone has less uncertainty and a clearer understanding of what to do.
Different Types of Work Breakdown Structure
With a Work Breakdown Structure ( WBS), there are three common methods of structuring work. They include phase-based structures, deliverable-based structures, and structures based on responsibility.
Deliverable oriented WBS
The delivery-oriented WBS (also known as product-oriented WBS) decomposes the scope of the project into smaller and more manageable deliverables. In order to complete the project, deliverables are tangible components that must be completed. Usually, they are a physical component or an item that needs to be achieved, obtained, or supplied as a result of project activities being executed.
These deliverables are either interim or final deliverables delivered to meet the requirements of the project. For construction projects, conceptual plans and specifications, tender documents and pre-construction mock-ups are examples of interim project deliverables. Examples of final project deliverables in a construction project which include concrete structures, structural steels, a building façade and a building mechanical system.
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