Table of Contents
1. Introduction to Work Breakdown Structure
1.1. What is a Work Breakdown Structure (WBS)?
-A 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.
-It is a deliverable-oriented breakdown of a project into smaller components, organized in a tree structure.
-The WBS defines and organizes the total scope of the project.
– Each descending level represents an increasingly detailed definition of the project work.
1.2. Importance of WBS in project management
– Provides a clear and detailed overview of all project tasks and deliverables
– Helps to effectively plan, execute, and control projects.
– Enables accurate cost and time estimation
– Facilitates resource allocation and assignment of responsibilities
– Serves as a basis for project scheduling and monitoring progress
– Improves communication among project stakeholders
– Helps to identify and manage project risks
– Ensures that all necessary work is accounted for and no unnecessary work is performed.
1.3. Real-life example: Constructing a multi-story office building
– Consider a project to construct a 10-story office building in a city center
– The project involves multiple deliverables such as site preparation, foundation, structural framework, mechanical and electrical systems, interior finishes, and landscaping
– A WBS for this project would start with the overall project at the top level
– The second level might include major deliverables such as:
– Site preparation
– Building structure
– Mechanical, electrical, and plumbing (MEP) systems
– Interior finishes
– Exterior work and landscaping
– Each of these deliverables would be further broken down into smaller components at the third, fourth, and fifth levels of the WBS
– For example, “Building structure” could be decomposed into foundation, structural framework, roof, and facade
– “MEP systems” could be broken down into HVAC, electrical, plumbing, and fire protection
– The lowest level of the WBS would consist of specific work packages such as “Install HVAC ductwork on 5th floor” or “Paint interior walls in lobby”
– By creating a detailed WBS, the project manager can ensure that all necessary work is identified, planned for, and completed in order to successfully deliver the office building project
2. WBS in PMBOK and APM BOK
2.1. PMBOK definition of WBS
– The PMBOK Guide defines the Work Breakdown Structure as “a deliverable-oriented hierarchical decomposition of the work to be executed by the project team to accomplish the project objectives and create the required deliverables”.
– It is a way of organizing and defining the total scope of the project by breaking it down into smaller, more manageable components.
2.2. WBS in the Scope Management Knowledge Area of PMBOK
– In the PMBOK Guide, the Work Breakdown Structure is a key component of the Project Scope Management Knowledge Area.
– The WBS is created as part of the “Create WBS” process, which falls under the “Planning Process Group” and the “Scope Management Knowledge Area”.
– The inputs to this process include the scope management plan, project scope statement, requirements documentation, and enterprise environmental factors.
– The main tool used in this process is decomposition, which involves subdividing project deliverables into smaller, more manageable components.
2.3. APM BOK definition of WBS
– The APM Body of Knowledge (APM BOK) defines the Work Breakdown Structure as “a hierarchical structure by which project elements are broken down, or decomposed”.
– The APM BOK also notes that the WBS shows the work required to create the project’s products, as defined in the Product Breakdown Structure (PBS).
2.4. Real-life example: Building a highway bridge
– Consider a project to construct a new highway bridge. The high-level deliverables in the WBS might include:
– Foundation
– Substructure (piers and abutments)
– Superstructure (girders, deck, and barriers)
– Approaches and roadway
– Lighting and signage
– Each of these deliverables would be further decomposed into smaller elements. For example, the “Foundation” deliverable might include:
– Excavation
– Piling
– Pile caps
– Footings
– The “Superstructure” deliverable could be broken down into:
– Steel girders
– Bridge deck
– Expansion joints
– Barriers and railings
– By creating a detailed WBS, the project team can ensure that all necessary work is accounted for, and the bridge construction project can be effectively planned, executed, and controlled.
3. Types of Work Breakdown Structures
3.1. Deliverable-based WBS
– Breaks down the project based on deliverables, such as products, services, or results
– Focuses on the project scope and what needs to be delivered
– The hierarchy captures what will be built rather than how it will be built
– The elements are physical components of the building or interim deliverables needed for completion
– Components are described using nouns rather than verbs
– Example: A deliverable-based WBS for a car project might include deliverables like interior, exterior, and electronics, which are further broken down into their components.
3.2. Phase-based WBS
– Breaks down the project into phases, such as initiation, planning, execution, control, and closure
– Focuses on the project lifecycle and when deliverables need to be completed
– Level 1 elements are typical project phases, while Level 2 elements are unique deliverables in each phase
– Requires work associated with multiple elements to be divided into the work unique to each Level 1 element
– Example: A phase-based WBS might include phases like requirements gathering, design, development, testing, and deployment
3.3. Real-life example: Constructing a residential housing complex
– Consider a project to construct a residential housing complex with multiple apartment buildings, amenities, and infrastructure
– A deliverable-based WBS for this project might include major deliverables such as:
– Site preparation (e.g., excavation, grading, utilities)
– Building structures (e.g., foundations, framing, roofing)
– Mechanical, electrical, and plumbing systems
– Interior finishes (e.g., drywall, flooring, painting)
– Exterior work (e.g., facades, landscaping, parking)
– Amenities (e.g., clubhouse, pool, fitness center)
– Each of these deliverables would be further decomposed into smaller components and work packages
– For example, “Building structures” could be broken down into individual apartment buildings, each with its own foundation, framing, and roofing work packages
– “Interior finishes” could include work packages for each apartment unit, such as installing drywall, flooring, and fixtures
– By creating a detailed deliverable-based WBS, the project team can ensure that all necessary work is identified, planned for, and completed to successfully deliver the residential housing complex
4. Creating a Work Breakdown Structure
4.1. Steps to create a WBS
1. Identify project scope and major deliverables
– Review project charter, scope statement, and other relevant documents
– Brainstorm with the project team and stakeholders to identify key deliverables
2. Decompose deliverables into smaller components
– Break down each major deliverable into sub-deliverables and work packages
– Ensure that each component is specific, measurable, and assignable
3. Assign codes to each component
– Use a numbering system to uniquely identify each component
– The coding helps in tracking and reporting progress
4. Determine work packages
– Identify the lowest level tasks required to complete each sub-deliverable
– Work packages should have a clear start and end point, and be assignable to a specific team or individual
5. Create WBS dictionary
– Develop a document that provides detailed information about each component in the WBS
– The dictionary should include task descriptions, responsible parties, start and end dates, and deliverables
4.2. WBS decomposition levels
– Level 1: Project title and final deliverable
– Level 2: Major project phases or high-level deliverables (control accounts)
– Level 3: Sub-deliverables or work packages
– Level 4 and beyond: Smaller tasks and activities required to complete work packages
– The number of levels depends on the project size and complexity
4.3. The 100% rule
– The WBS must include 100% of the work defined by the project scope
– All deliverables, both internal and external, must be accounted for
– The sum of the work at the “child” level must equal 100% of the work at the “parent” level
– The WBS should not include any work that falls outside the actual scope of the project
4.4. Real-life example: Building a water treatment plant
– Consider a project to construct a new wastewater treatment plant
– The Level 1 deliverable is the completed plant
– Level 2 deliverables could include:
– Site preparation
– Foundations and structures
– Treatment process equipment
– Piping and utilities
– Electrical and control systems
– Level 3 and 4 would further break down each of these deliverables
– For example, “Treatment process equipment” could include:
– Screening and grit removal
– Primary clarifiers
– Aeration basins
– Secondary clarifiers
– Disinfection system
– The WBS would continue to decompose the work until reaching the work package level
– The 100% rule ensures that all necessary work is accounted for and within scope
5. WBS Dictionary
5.1. What is a WBS Dictionary?
– A WBS Dictionary is a document that provides detailed information about each element in the Work Breakdown Structure (WBS)
– It complements the WBS by offering descriptions, deliverables, activities, and scheduling information for each task
– Key components of a WBS Dictionary include:
– WBS Code: Unique identifier for each WBS element
– Element Name: Task or component name
– Description of Work: Detailed explanation of the task and its scope
– Deliverables: Specific outcomes or outputs of the task
– Responsible Party: Individual or team responsible for completing the task
– Estimates: Time and cost estimates for the task
– Schedule Dates: Start and end dates for the task
– Resources Required: Personnel, equipment, and materials needed
– Dependencies: Relationships with other tasks
5.2. Importance of a WBS Dictionary
– Clarifies the scope of work for each WBS element, reducing ambiguities and preventing scope creep
– Provides a clear understanding of tasks, responsibilities, and expectations for all project stakeholders
– Helps in managing resources efficiently and achieving project objectives within given constraints
– Serves as a communication tool, demystifying the WBS and increasing its usability
– Complements the graphical representation of the WBS by adding detailed information
– Enables effective project planning, execution, monitoring, and control
5.3. Real-life example: Constructing a shopping mall
– Consider a project to construct a large shopping mall with multiple floors, retail spaces, food courts, and parking facilities
– The WBS for this project would include major deliverables such as:
– Site preparation
– Foundation and structural work
– Mechanical, electrical, and plumbing (MEP) systems
– Interior finishes and fit-outs
– Exterior work and landscaping
– The WBS Dictionary would provide detailed information for each of these deliverables and their sub-components
– For example, under “Interior finishes and fit-outs,” the WBS Dictionary might include:
– WBS Code: 4.1
– Element Name: Tenant A Retail Space Fit-Out
– Description of Work: Complete interior fit-out for Tenant A’s 5,000 sq. ft. retail space, including partitions, flooring, lighting, and fixtures
– Deliverables: Completed retail space as per Tenant A’s specifications
– Responsible Party: Interior Fit-Out Contractor
– Estimates: 4 weeks, $250,000
– Schedule Dates: Start 01/09/2023, End 30/09/2023
– Resources Required: Fit-out crew, materials, equipment
– Dependencies: MEP rough-in complete, Tenant A design approved
– By providing this level of detail for each WBS element, the WBS Dictionary ensures that all stakeholders have a clear understanding of the work involved in constructing the shopping mall
6. Benefits of using a WBS
6.1. Improved scope management
– A WBS provides a clear and comprehensive view of the project scope
– It ensures that all necessary work is included and no unnecessary work is performed
– By breaking down the project into smaller, manageable components, a WBS helps prevent scope creep
– It serves as a reference point for evaluating the impact of scope changes
6.2. Better communication and team alignment
– A WBS acts as a communication tool, providing a common language for all stakeholders
– It clarifies roles, responsibilities, and expectations for each team member
– By visualizing the project hierarchy, a WBS helps team members understand how their work fits into the bigger picture
– It promotes collaboration and accountability among team members
6.3. More accurate cost and time estimates
– Breaking down the project into smaller tasks enables more accurate cost and time estimation
– A WBS provides a framework for bottom-up estimating, where costs and durations are estimated at the work package level and then rolled up
– It helps identify resource requirements and optimize resource allocation
– Accurate estimates lead to better budgeting and scheduling, reducing the risk of cost overruns and delays
6.4. Real-life example: Building a university campus
– Consider a project to construct a new university campus, including academic buildings, dormitories, sports facilities, and infrastructure
– A WBS for this project might include major deliverables such as:
– Site preparation and infrastructure
– Academic buildings (classrooms, labs, offices)
– Student housing and dining facilities
– Sports and recreation facilities
– Landscaping and outdoor spaces
– Each of these deliverables would be further broken down into sub-deliverables and work packages
– By creating a comprehensive WBS, the project team can:
– Ensure all necessary components of the campus are included in the scope
– Clearly communicate the project structure and responsibilities to all stakeholders
– Develop accurate cost and time estimates for each deliverable and work package
– Monitor progress and manage scope changes throughout the project lifecycle
– The WBS serves as a roadmap for the successful planning, execution, and delivery of the university campus project
7. Best practices for creating and using a WBS
7.1. Involve the project team
– Engage the project team in the WBS creation process to gain their input and buy-in
– Leverage the team’s expertise to identify all necessary deliverables and work packages
– Collaboratively developing the WBS fosters a shared understanding of the project scope and responsibilities
– Involving the team in WBS creation increases their commitment to the project’s success
7.2. Use nouns, not verbs
– Describe WBS elements using nouns and adjectives, not verbs
– Focus on deliverables and outcomes, not activities or tasks
– Using nouns helps maintain clarity and avoids confusion between the WBS and the project schedule.
– Example: “Access road” instead of “Build access road”
7.3. Avoid overlapping deliverables
– Ensure that each WBS element is mutually exclusive and does not overlap with others in scope
– Overlapping deliverables can lead to duplication of effort, confusion, and inaccurate cost or resource estimates
– Clearly define the boundaries and scope of each deliverable to maintain clarity and accountability
7.4. Real-life example: Constructing a sports stadium
– Consider a project to construct a new sports stadium with a seating capacity of 50,000
– Involve the project team, including architects, engineers, contractors, and stakeholders, in developing the WBS
– The high-level WBS elements (Level 2) might include:
– Site preparation
– Foundation and structural work
– Seating and spectator areas
– Playing field and sports facilities
– Mechanical, electrical, and plumbing systems
– Exterior work and landscaping
– Each of these elements would be further decomposed into Level 3 and beyond, using nouns to describe the deliverables
– For example, “Seating and spectator areas” might include:
– Lower tier seating
– Upper tier seating
– VIP boxes and suites
– Concourses and walkways
– Restrooms and concessions
– Ensure that each deliverable is mutually exclusive and clearly defined to avoid overlap
– By involving the team, using nouns, and avoiding overlap, the WBS for the sports stadium project will provide a clear and comprehensive breakdown of the scope, facilitating effective planning, execution, and control
8. Common pitfalls to avoid
8.1. Too much or too little detail
– Finding the right level of detail is crucial for an effective WBS
– Too much detail can lead to micromanagement, slowing down project progress
– Work packages should not be so detailed that they represent tasks lasting only a few hours
– Too little detail makes it difficult for the project manager to effectively manage the project
– Insufficient detail in the WBS can result in inaccurate scheduling and resource estimation
– Aim for a level of detail where work packages are manageable and can be easily assigned to team members
8.2. Confusing WBS with a project schedule
– The WBS is not a project schedule and should not include task durations, start/end dates, or dependencies
– The WBS is a hierarchical decomposition of the project scope, focusing on deliverables and work packages
– The project schedule, on the other hand, adds a time dimension to the WBS, defining when each task will be performed
– Avoid discussing task sequencing or timelines when creating the WBS to prevent confusion
8.3. Real-life example: Building a power plant
– Consider a project to construct a new power generation plant
– A high-level WBS for this project might include:
– Site preparation
– Foundations and structures
– Mechanical systems (e.g., turbines, generators)
– Electrical systems (e.g., switchgear, transformers)
– Instrumentation and control systems
– Balance of plant (e.g., cooling towers, water treatment)
– Decomposing these elements further, the “Mechanical systems” branch might include:
– Steam turbine
– Gas turbine
– Generators
– Condensers
– Pumps and piping
– To avoid too much detail, individual components like valves or sensors should not be included in the WBS
– To avoid too little detail, ensure that work packages are defined at a level where they can be effectively managed and assigned
– Focus on deliverables and work packages, not on scheduling or task sequencing, to maintain clarity and avoid confusion with the project schedule
9. Conclusion
9.1. Recap of key points
– A Work Breakdown Structure (WBS) is a hierarchical decomposition of the total scope of work required to complete a project
– The WBS breaks down the project into smaller, more manageable components, providing a clear and structured view of the work
– Key benefits of using a WBS include improved scope management, better communication and team alignment, and more accurate cost and time estimates
– Best practices for creating and using a WBS involve engaging the project team, using nouns to describe deliverables, and ensuring that each element is mutually exclusive
– Common pitfalls to avoid include having too much or too little detail and confusing the WBS with a project schedule
9.2. Importance of WBS for successful project management
– The WBS serves as the foundation for project planning, execution, and control
– It provides a clear understanding of the project scope and helps prevent scope creep
– The WBS enables effective resource allocation, risk identification, and progress tracking
– By breaking down the project into manageable components, the WBS makes the project more achievable and increases the likelihood of success
9.3. Real-life example: Constructing an airport terminal
– Consider a project to construct a new airport terminal to accommodate increased passenger traffic and larger aircraft
– The WBS for this project would start with the overall project deliverable (the completed terminal) and then break it down into major components such as:
– Site preparation and foundations
– Terminal building structure
– Mechanical, electrical, and plumbing systems
– Interior finishes and furnishings
– Baggage handling systems
– Passenger boarding bridges
– Landscaping and exterior work
– Each of these major components would be further decomposed into sub-deliverables and work packages
– For example, “Interior finishes and furnishings” might include:
– Flooring
– Wall coverings
– Ceilings
– Lighting fixtures
– Seating and furniture
– Signage and wayfinding
– By creating a comprehensive WBS, the project team can ensure that all necessary work is identified, planned for, and completed to successfully deliver the new airport terminal
In conclusion, the Work Breakdown Structure is a powerful tool for project managers to plan, execute, and control projects effectively. By breaking down complex projects into smaller, more manageable components, the WBS provides a clear roadmap for project success. When applied to real-life projects like constructing an airport terminal, the WBS helps ensure that all necessary work is accounted for, resources are allocated efficiently, and the project is completed on time, within budget, and to the required quality standards.
Additional Reads:
Work Breakdown Structre (WBS) (by Project Manager.com)
https://venunataraj.com/10-steps-to-master-wbs-in-construction-management-part-1
https://venunataraj.com/10-steps-to-master-wbs-in-construction-management-part-2
https://venunataraj.com/10-steps-to-master-wbs-in-construction-management-part-3