Creating the project work breakdown structure (WBS) is the most important part of the scope management activities because it’s where you actually figure out all the work you’re going to do. It is the process of subdividing project deliverables and project work into smaller, more manageable components, in order to provide a framework of what has to be delivered at the end of the project.
Project Scope Definition
In the project context, the term “scope” can refer to the work performed to deliver a product, service, or result with the specified features and functions. The term “project scope” is sometimes viewed as including product scope. Project life cycles can range along a continuum from predictive approaches at one end to adaptive or agile approaches at the other. In a predictive life cycle, the project deliverables are defined at the beginning of the project and any changes to the scope are progressively managed. In an adaptive or agile life cycle, the deliverables are developed over multiple iterations where a detailed scope is defined and approved for each iteration when it begins.
In predictive projects, the scope baseline for the project is the approved version of the project scope statement, project work breakdown structure (WBS), and its associated WBS dictionary. A baseline can be changed only through formal change control procedures and is used as a basis for comparison while executing and monitoring the project.
Completion of the project scope is measured against the project management plan, while completion of the product scope is measured against the product requirements. The term “requirement” is defined as a condition or capability that is required to be present in a product, service, or result to satisfy an agreement or other formally imposed specification.
One of the most important activities of planning and managing the project scope is creating the project work breakdown structure (WBS), which can be defined as 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. The WBS organizes and defines the total scope of the project and represents the work specified in the current approved project scope statement.
Creating the WBS in Project Management
There is no “right” way to construct a project work breakdown structure (WBS). In practice, the chart structure is used quite often. (This structure resembles an organization chart with different levels of detail.) But a WBS could be composed in outline form as well. The choice is yours. The technique you will highly rely on while creating the work breakdown structure is the decomposition. Decomposition is a technique used for dividing and subdividing the project scope and project deliverables into smaller, more manageable parts.
The work package is the work defined at the lowest level of the WBS for which cost and duration can be estimated and managed. 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.
As per the project management institute (PMI) standard, decomposition is a five-step process:
- Identify the deliverables and work. This step involves identifying all the major project deliverables and related work. You can use the expert judgment technique to analyze the project scope statement and identify the major deliverables.
- Organize the project work breakdown structure (WBS). This step involves organizing the work of the project and determining the WBS structure.
- Decompose the WBS components into lower-level components. WBS components, like the deliverables and requirements, should be defined in tangible, verifiable terms so that performance and successful completion are easily measured and verified.
- Assign identification codes. This step is a process where you assign identification codes or numbers to each of the WBS components.
- Verify the project work breakdown structure (WBS). This step is a verification step. Examine the decomposition to determine whether all the components are clear and complete. Determine whether each component listed is absolutely necessary to fulfill the requirements of the deliverable, and verify that the decomposition is sufficient to describe the work.
A project work breakdown structure (WBS) structure may be created through various approaches. Some of the popular methods include the top-down approach, the use of organization-specific guidelines, and the use of WBS templates. A bottom-up approach can be used to group subcomponents. The WBS structure can be represented in a number of forms, such as:
- Using phases of the project life cycle as the second level of decomposition, with the product and project deliverables inserted at the third level, as shown in figure below.
- Incorporating subcomponents that may be developed by organizations outside the project team, such as contracted work. The seller then develops the supporting contract WBS as part of the contracted work.
Decomposition of the upper-level WBS components requires subdividing the work for each of the deliverables or subcomponents into its most fundamental components, where the WBS components represent verifiable products, services, or results. If an agile approach is used, epics can be decomposed into user stories.
The project work breakdown structure (WBS) may be structured as an outline, an organizational chart, or other method that identifies a hierarchical breakdown. Verifying the correctness of the decomposition requires determining that the lower-level WBS components are those that are necessary and sufficient for completion of the corresponding higher-level deliverables.
Different deliverables can have different levels of decomposition. To arrive at a work package, the work for some deliverables needs to be decomposed only to the next level, while others need additional levels of decomposition. As the work is decomposed to greater levels of detail, the ability to plan, manage, and control the work is enhanced. However, excessive decomposition can lead to nonproductive management effort, inefficient use of resources, decreased efficiency in performing the work, and difficulty aggregating data over different levels of the WBS.
Work Breakdown Structure Levels
Although the project manager is free to determine the number of levels in the WBS based on the complexity of the project, all project work breakdown structure (WBS) structures start with the project itself. Some WBS structures show the project as level one. Others show the level under the project, or the first level of decomposition, as level one.
The first level of decomposition might be the deliverables, phases, or subprojects. Remember that the first level of decomposition is actually the second level of the WBS because the project level is the first level. The levels that follow show more and more detail and might include more deliverables followed by requirements.
Each of these breakouts is called a level in the WBS. The lowest level of any WBS is called the work package level. The goal is to construct the WBS to the work package level where you can easily and reliably estimate cost and schedule dates. Keep in mind that not all of the deliverables may need the same amount of decomposition.
Also realize that performing too much decomposition can be as unproductive as not decomposing enough. When the work outlined in the work package level is easily understood by team members and can be completed within a reasonable length of time, you’ve decomposed enough. If you decompose to the point where work packages are describing individual activities associated with higher-level elements, you’ve gone too far.
Defining Work Packages
Work packages are the components that can be assigned to one person, or a team of people, with clear accountability and responsibility for completing the assignment, and they can be monitored and controlled throughout the project. Assignments are easily made at the work package level but can be made at any level in the WBS. The work package level is where time estimates, cost estimates, and resource estimates are determined. Work package levels on large projects can represent sub projects that are further decomposed into their own work breakdown structures.
They might also consist of project work that will be completed by a vendor, another organization, or another department in your organization. If you’re giving project work to another department in your organization, you’ll assign the work packages to individual managers, who will in turn break them down into activities.
Work packages might be assigned to vendors or others external to the organization. For example, perhaps one of the deliverables in your project is special packaging and a vendor is responsible for completing this work. The vendor will likely treat this deliverable as a project within its own organization and construct its own WBS with several levels of decomposition.
As a conclusion, the project work breakdown structure maps the deliverables of the project with sub-deliverables and other components stemming from each major deliverable in a tree or chart format. Simply put, a work breakdown structure (WBS) is a deliverable-oriented hierarchy that defines and organizes the entire scope of work of the project and only the work of the project. The items defined on the WBS come from the approved scope statement. Like the scope statement, the WBS serves as a foundational agreement among the stakeholders and project team members regarding project scope.
The WBS should detail the full scope of work needed to complete the project. This breakdown will smooth the way for estimating project cost and time, scheduling resources, and determining quality controls later in the Planning processes. Project progress will be based on the estimates and measurements assigned to the WBS segments. So, again, accuracy and completeness are required when composing your work breakdown structure (WBS).
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