1. Basic concepts of WBS
Work Breakdown Structure : WorkBreakdownStructure (referred to as WBS). Correspondence should be executed by the project team in order to achieve the project goals and create the necessary deliverables, decomposed according to the levels of deliverables. WBS organizes the entire scope of the project together and clarifies it, that is, a project is broken down according to certain principles, the project is broken down into tasks, and the tasks are broken down into items of work, and then the items of work are assigned to everyone until The decomposition can not go on.
Namely: Project→Task→Work→Personal.
WBS is always at the center of the planning process, and is also an important basis for making schedules, resource requirements, cost budgets, risk management plans, and procurement plans.
2. Basic content of WBS
2.1 Requirements to be met to create WBS
1. A task should be in one place in the WBS and should only appear in one place in the WBS.
2. The content of a task in WBS is the sum of all WBS items under it.
3. A WBS item can only be responsible by one person. Even though many people may work on it, only one person can be responsible, and the others can only be participants.
4. The WBS must be consistent with the implementation method in actual work.
5. Project team members should be actively involved in the creation of WBS to ensure the consistency of WBS.
6. Each WBS item must be documented to ensure accurate understanding of the scope of work included and not included.
7. WBS must be able to adapt to unavoidable changes while maintaining the work content of the project normally according to the scope statement.
8. The definition of WBS work package does not exceed 40 hours, and it is recommended that it be 4-8 hours.
9. The level of WBS does not exceed 10 levels, and it is recommended to be at levels 4-6.
2.2 Decomposition method
Decomposed according to the physical structure of the product.
Break down by product or project function.
Decompose according to the implementation process.
Break down according to the geographical distribution of the project.
Break down according to the goals of the project.
Break down by department.
Break down by function.
2.3 Representation method
WBS can be represented by a tree-shaped hierarchical structure diagram or an indented table at the
beginning of a line . The WBS level of the tree-shaped structure diagram is clear and very intuitive. The structure is very strong, but it is not easy to modify the work breakdown structure, and it is difficult to show the panorama of the project for large and complex projects. Due to subjectivity, there are generally more in small and moderate projects.
3. WBS structure
Work-work tasks that can produce tangible results; breakdown-a hierarchical structure of progressive subdivision and classification; structure-organize the parts according to a certain pattern. According to these concepts, WBS has corresponding constituent factors corresponding to it:
3.1 Structured coding
Coding is the most significant and critical component of WBS. First, coding is used to thoroughly structure WBS. Through the coding system, we can easily identify the hierarchical relationship, grouping category and characteristics of WBS elements. And due to the development of modern computer technology, coding actually closely connects WBS information with organizational structure information, cost data, schedule data, contract information, product data, report information, etc.
3.2 Work package
Work package (work package) is the lowest element of WBS, general work package is the smallest "deliverable", these deliverables can easily identify the activities, costs, organization and resource information to complete it.
For example: the pipeline installation work package may include several activities such as pipeline support production and installation, pipeline connection and installation, and tightness inspection; it includes transportation/welding/pipe production labor costs, pipeline/metal accessory material costs and other costs; Documents such as reports/inspection results, etc.; as well as information on the responsibility of assigned work teams, etc.
It is the above organization/cost/schedule/performance information that makes the work package and even WBS the basis of project management. Based on the above point of view, a WBS for project management must be decomposed to the work package level to be able to make it an effective management tool.
3.3 WBS element
WBS elements are actually "nodes" in the WBS structure. The popular understanding is the "frames" on the "organizational chart". These boxes represent independent, subordination/aggregation relationships. Deliver results". After decades of summarizing, most organizations tend to think that the WBS structure must be related to the project goals and must be oriented towards the final product or deliverable. Therefore, the WBS element is more suitable for describing the noun composition of the output product (effictive WBS, Gregory T. Haugan ).
The reason is obvious. Different organizations, cultures, etc. use different methods, procedures, and resources to complete the same work, but their results must be the same and must meet the specified requirements. Only by grasping the core deliverables can the project be controlled and managed most effectively; on the other hand, only by identifying the deliverables can the methods, procedures and resources used by internal/external organizations to complete the work be identified. The work package is the lowest WBS element,
3.4 WBS dictionary
The standardization and standardization of management has always been the goal pursued by many companies, and the WBS dictionary is such a tool.
It is used to describe and define the document of the work in the WBS element. The dictionary is equivalent to the specification of a certain WBS element, that is, the work that the WBS element must complete and the detailed description of the work; the description of the work product and the corresponding standard standard; the upper-level relationship of the element and the input-output relationship of the element result.
At the same time, the WBS dictionary also plays a huge role in defining the scope of the project clearly. It makes the WBS easy to understand and acceptable to participants outside the organization (such as contractors). In the construction industry, the bill of quantities specification is a typical WBS dictionary at the work package level.
4. The process of creating WBS
The process of creating WBS is very important, because in the process of project decomposition, the project manager, project members and all functional managers involved in the project must consider all aspects of the project.
The process of formulating WBS is:
1. Obtain Scope Statement or Statement of Wok (when subprojects are contracted).
2. Convene relevant personnel, collectively discuss all major project work, and determine the method of project work breakdown.
3. Break down the project work. If there are ready-made templates, they should be used as much as possible.
4. Draw the hierarchical structure diagram of WBS. Some work at higher levels of WBS can be defined as sub-projects or sub-life cycle stages.
5. Subdivide the main project deliverables into smaller, manageable components or work packages. The work package must be detailed enough to estimate the work package (cost and duration), arrange the schedule, make a budget, and assign responsible personnel or organizational units.
6. Verify the correctness of the above decomposition.
7. If it is found that lower-level items are not necessary, modify the components. If necessary, establish a numbering system.
8. With the progress of other planned activities, continuously update or revise the WBS until all the work is covered.
5. Types of WBS
5.1 Outline work breakdown structure (SWBS: Summary WBS)
The outline work breakdown structure is a guiding and strategic work breakdown structure. The decomposition structure has only the above three levels: the
first level: the entire system is the defense equipment item, such as: aircraft system, electronic system, missile system, ordnance system, space system and ground vehicle system.
Level 2: Major units of defense equipment projects, such as aviation vehicles, ships, system experiments, and data.
The third level: subordinate to the second level of units, such as airframes, propulsion devices, materials, services and technical publications.
5.1 Project outline work breakdown structure
Project outline work breakdown structure is a work breakdown structure obtained by tailoring the outline work breakdown structure for a specific project.
5.3 Standard Work Breakdown Structure of Engineering Company
5.4 Contract Work Breakdown Structure (CWBS: Contract WBS)
The contract work breakdown structure is a complete work breakdown structure applicable to a specific contract or procurement activity.
CWBS summarizes the tasks of the project, determines the relationship between these tasks and the organization and technical status of the project, and determines the logical constraint framework for the relationship between the performance, technical goals, schedule and cost of the project. The work breakdown structure of the contract should be consistent with the level specified in the contract. The contract should indicate at which level of the contract the cost is accumulated. The contract WBS extension level used by the contractor to control its expenses shall have the ability to trace the accumulation of expenses.
In some other specific application areas, other common breakdown structures mainly include:
A. Contract Work Breakdown Structure (CWBS)-it is mainly used to define the level of reports provided by the seller to the buyer, and is usually not as good as the work used by the seller in management work The breakdown structure (WBS) is detailed.
B. Organizational breakdown structure (OBS)-it is used to show which organizational unit each work element is assigned to.
C. Resource breakdown structure (RBS)-it is a variation of the organizational breakdown structure, usually used when assigning work elements to individuals.
D. Bill of Materials (BOM)-expresses the hierarchical level of the actual parts, components and components required to manufacture a processed product.
E. Project breakdown structure (PBS)-it is basically the same concept as work breakdown structure (WBS).
6. Main purpose and function
6.1 Role
1. Clearly and accurately state the scope of the project;
2．Assign personnel to each independent unit and specify the corresponding responsibilities of these personnel;
3. For each independent unit, estimate the time, cost and resource requirements to improve the accuracy of time, cost and resource estimation;
4. To plan, cost, schedule, quality, safety and cost control or forge common ground, determine the project schedule baseline measurement and control;
5. Link the project work with the project’s financial accounts;
6. Facilitate the division and assignment of responsibilities;
7. Determine the work content and work sequence;
8. Estimate the overall cost of the project and the whole process.
6.2 Purpose
WBS is a planning and design tool for describing ideas. It helps project managers and project teams to determine and effectively manage project work.
- WBS is a structural design tool that clearly expresses the interrelationships between projects.
- WBS is a planning tool that displays the overall picture of the project and specifies the various tasks that must be completed to complete the project
- WBS defines milestone events and can report project completion to senior management and customers as a reporting tool for project status.
- WBS prevents omission of project deliverables.
- WBS helps project managers focus on project goals and clarify responsibilities.
- WBS establishes visual project deliverables in order to estimate workload and allocate work.
- WBS helps improve the accuracy of time, cost and resource estimates.
- WBS helps the establishment of the project team and obtains the commitment of the project personnel.
- WBS defines a benchmark for performance measurement and project control.
- WBS assists in communicating clear job responsibilities.
- WBS establishes a framework for the formulation of other project plans.
- WBS helps analyze the initial risks of the project.
7. More understanding
Reference: WBS concept, decomposition strategy, function, decomposition principle and method
Understanding of WBS From the above explanation, we draw the following conclusions. WBS defines the project and clarifies the tasks of the project. This shows that WBS plays an important role in project management, so "without WBS, there would be no project management." The understanding of WBS definition should focus on the following two aspects:
The first aspect is the unit of WBS, that is, the object of the WBS hierarchy. It is guided by "Deliverables" instead of "ScheduleActivity".
The lowest level of WBS is WorkPackage (work detail), which includes the planned activities and progress milestones necessary to complete the deliverables or project work components of the work detail.
Why is the bottom level of WBS not ScheduleActivity (planned activity) but WorkPackage (work detail)?
First of all, WBS is used as a tool and technology for project scope management. The focus of project scope management is the component part of the project. It is oriented to deliverables, not processes.
Secondly, WBS defines the project and its components, and is the basis for the definition of ScheduleActivity, rather than defining ScheduleActivity.
Third, ScheduleActivity (planned activity) is a single component of the project schedule, not a component of WBS. For this, many people may have difficulty understanding. Because the habitual argument is that the activity is composed of various specific tasks, and the above definition is the opposite of the literal definition of PMBOK, but in essence, the two should be the same, but the argument is different. Because before project management was introduced to China, we equated activities with projects.
The second aspect is the structure of WBS. The structure of WBS includes a scientific logical structure, rather than a single, discrete, and discontinuous description structure of results in time sequence.
The structure of WBS is deduced by logic, and it is very rigorous through layered containment relationships. Structure is an important feature of WBS. WBS logical structure errors will directly lead to errors in the project implementation process, and serious project failures. "Do the right thing, do the right thing" is our motto for project management. The first thing WBS solves is the problem of "do the right thing". Only when it is clear that "do the right thing", "do the right thing" has the foundation , So we say that WBS is an important cornerstone of modern project management.