ANATOMY OF A WBS

The elements that appear in the three types of WBS (Product, Service, and Results) are covered in this section.

All WBSs have two or more of the five types of Level 2 elements shown in Figure 2-2.

FIGURE 2-2 Types of Level 2 Elements

The first three types of elements are derived from the three types of projects indicated in the definition of a project in the PMBOK® Guide: “A temporary endeavor undertaken to create a unique product, service, or result.” For all three types of projects, there are one or more deliverables or outputs corresponding to the types of elements discussed here that are the basis for developing the WBS.

The last two types of elements in Figure 2-2 are supporting elements that are needed for a complete definition of the scope of a project (and to meet the 100 percent rule).

The five types of Level 2 elements are:

1. Product Breakdown Elements: The subdivision based on the physical structure of the product(s) being delivered is the most common basis for a WBS and the easiest WBS to develop. These projects have a tangible output product—software, a building, a dam, an airplane, a user’s manual, and so on—and all have a natural structure. Alternatively, there may be multiple products or systems delivered, which occurs in an airport ground surveillance system, a DoD unmanned aircraft vehicle system, an integrated Coast Guard deepwater ship system, or an orbiting space laboratory system.

2. Service Breakdown Elements: Service projects do not have a tangible, structured deliverable. The output is a defined body of work done for others: conference, party, wedding, vacation trip, and so on. The work breakdown is a logical collection of related work areas.

3. Results Breakdown Elements: Results projects do not have a unique, tangible, structured deliverable that is known in detail at the start of the project. The output is a consequence—a result—of a process that involves a product or an outcome: cancer research, new drug development, smoking reduction, and so on. The work breakdown is a series of accepted steps, stages, or processes. A very common and special case of the Results Breakdown type of WBS occurs in information technology (IT) programs.

4. Cross-Cutting Elements: This is a breakdown of items that cut across the product, such as architectural design, assembly, or system testing, or that are common to more than one WBS element at the same level. These elements are usually technical and supportive in nature. There may be more than one element of this characteristic at Level 2. While there is no restriction, these types of elements are rare in Service or Results projects, except for project management, as discussed later.

5. Project Management Element: This is a breakdown of the managerial responsibilities and managerial activities of the project. It includes such items as reports, plans, project reviews, and other activities of the project manager or his or her staff. (Conceptually, these are the overhead of the project.) There normally is only one of this type of WBS element, but it exists on all projects as a Level 2 element.

Product Breakdown Elements

The product breakdown element in a WBS is the decomposition of the natural, physical structure of the output product being developed. This is apparent in Figures 1-1 and 1-2, which show the elephant breakdown structure. For building a garage, one of the elements on Level 2 (the products) is “Garage,” and Level 3 elements for “Garage” could be Materials, Foundation, Walls, Roof, and Utilities, as shown in Figure 1-6. There may be more than one output product or major deliverable at Level 2. For the garage project, the “Landscaped Grounds” is also an end item or deliverable, and the project is not complete until all the plants have been planted and the ground prepared as described in the contract statement of work (SOW) or drawing. An operator’s manual may be an additional output or deliverable item if the project is a new, high-speed lawn mower. If writing a book, the physical book would be the deliverable. If you were developing software, the documented source code, the manuals, and CD-ROM with the executable program and installation software would be the deliverables.

The product breakdown element usually has more levels than the “Cross-Cutting” or “Project Management” elements. Some parts of the product breakdown element may require decomposition to a greater level than others because of the nature of the product and its components. This can be seen in the WBS for the garage, Figure 1-6. If a major component of the garage is to be subcontracted, such as the walls, it becomes a work package, the lowest level necessary in the WBS. Further decomposition of the WBS would be the responsibility of the subcontractor, and the walls could be considered a subproject. The subcontractor WBS would have the walls as level 1 and the breakdown in Figure 1-6 as the second level. In large projects, such as construction of a new athletic stadium, subcontractor WBSs may have many levels.

In product breakdown elements, work packages can be assigned to either organizations or individuals, but individual resources are assigned only at the activity level.

Service Breakdown Elements

A WBS for a project where there is no tangible product, but where the objective is a service provided for someone or for a group, has a service breakdown element, which requires a different approach to decomposition. The decomposition is based on a logical grouping of similar and related work elements, functions, or skills. For example, all the work related to lodging on a project whose objective was a vacation trip to Asia could be located under the “Lodging” element, which could be further decomposed to the city or cities where the lodging was to occur. Activities may include making reservations, getting confirmations, making deposits, getting maps or instructions, and so on. There is usually a main event or objective for this type of project, such as a wedding, a dinner party, or putting on a conference. In these types of projects, all the WBS elements except “Project Management” represent a type of service provided, performed, or arranged. This is shown in the partial WBS presented in Figure 2-3.

FIGURE 2-3 Service WBS—International Conference Project

These types of WBSs are frequently developed initially from the bottom up, starting with a list of activities and grouping them into logical categories or functions.

The basis for each Level 2 element is that it represents a logical grouping of tasks that can be discretely described. Furthermore, each element at every level lends itself to being assigned to a single person or organization for performing or coordinating the group of work described in the WBS element descriptor.

The decomposition of the Level 2 and lower elements is based on the criteria that the child elements are related to the parent, and the key word is “grouping.” For example, the breakdown of “Transportation” could be “1. Airport; 2. Hotel-Conference Shuttle; 3. Tour Buses” and so on, all of which are related to transportation. Also, note that the breakdown of “Presentations” in Level 3 includes Level 4 elements that all relate to the presentations. This is different from a Product WBS, where the next level breakdown would be parts of the “Presentation,” not just related items.

Adding elements at Level 2 also focuses attention on the function and can improve the planning. For example, in Figure 2-3, if security is a concern, it should be added at Level 2, rather than being spread at Level 3 or lower in other elements. In this manner, all aspects of security would be grouped and focused, and it is more likely that all important security tasks would be identified.

It is important to note that the 100 percent rule applies, and that the WBS needs to be analyzed for completeness at every level by the project team. Every task needs a WBS parent; in the process of brainstorming the task list, additional WBS elements may need to be added. Getting stake-holders involved in developing the WBS for a new class-of-service project is more important in a service project than in a product or results project because there is no natural structure or sequence of elements to provide a hierarchy. However, if you worked for an events management firm, you would have a template or normal hierarchy based on previous projects.

Frequently, a large number of detailed activities need to be performed under each work package, much like a checklist. The planning and scheduling document may be a combination of a network diagram to identify sequential relationships of major tasks and checklists to make sure all the small details are identified and assigned.

The WBS for a service project works well as a template for future similar projects. All big weddings are similar in the major functions: They need a church (or synagogue, mosque, etc.), attendants, receptions, showers, invitations, and so on. Likewise, the WBSs for all conferences, parties, vacation trips, and so on are similar, at least at Level 2 and perhaps at Level 3.

Results Breakdown Elements—Generic Projects

Similar to a service project, the results type of project does not have a well-structured primary product as a deliverable but may have several products that collectively achieve the desired result. Such a project does, however, have a series of well-defined steps that are planned—it is a process-based project—and will have a results breakdown element.

Figure 2-4 is the WBS for a project whose result is the implementation of a Hazard Analysis Critical Control Point (HACCP) system in a food processing plant. The objective of this project is to convert a traditional food processing line from one where quality is achieved by inspection of the end product to one where quality is planned, through process controls applied at various critical control points.

FIGURE 2-4 Results WBS—HACCP Implementation Project

In this type of project, where the result is the successful implementation of a HACCP system, the same six steps are performed for each processing line or project. It is the same whether it is frozen seafood cakes, packaged chicken parts, or canned soup. There is also a series of steps at Level 3 and below that are prescribed and performed. Because every plant is different and every project is unique, the intermediate outputs from each step, while similar in name, are quite different in content.

For similar “results-type” projects, such as a HACCP system in a chicken processing plant or in food preparation in an institution, the WBS for the top levels are the same or very similar if the same result is to be achieved, that is, a HACCP system for safe processed food.

In another example, the Level 2 and 3 elements (or steps) for a project to develop a new drug to be approved by the Food and Drug Administration would be similar for any new drug development.

Again, the 100 percent rule applies, and the team must carefully review the child elements of each parent at each level to ensure that all the work is identified. People who are familiar with or expert in the process should be used in this analysis. The goal is the same as with any WBS: to ensure that all the work that needs to be performed to meet the project objectives is identified.

Results Breakdown Elements—Information Technology Projects

An IT project is a results project because it does not have a well-structured primary product as a deliverable but has several products that collectively achieve the desired result. IT projects are a special category or type of WBS and are a combination of processes and products that are designed to achieve a result. That result is usually the implementation of an IT system to perform a specified function. Large IT systems fit the definition of a “program” and have a top-level WBS like that shown in Figure 2-5.

FIGURE 2-5 Information Technology Program

See Example 6 in Chapter 10 for the further decomposition and description of the lower levels of this generic IT WBS.

Another example that is also discussed further in Chapter 10 is the WBS for an Enterprise Resource Planning (ERP) implementation, as shown in Figure 2-6.

FIGURE 2-6 ERP Implementation IT Project

In Figures 2-5 and 2-6, the project work moves in stages from left to right, starting with project initiation and analysis. Project management in both figures is cross-cutting and related to all the other stages or WBS elements.

Cross-Cutting Elements

Cross-cutting elements contain work that is shared with peer WBS elements at each level. In a Product WBS, the cross-cutting element represents work that either supports the other WBS elements at the same level or is common to the WBS elements at that level; cross-cutting elements may also be a next step in a process that results in a product. An example of work that supports other elements is an element such as “Architectural Design”; an example of work that is common to the WBS elements at that level is “Project Management”; and an example of a next step in a process that results in a product is “Final Inspections,” “Assembly,” or “System Test.” There may be more than one element of this characteristic at Level 2. As a generality, the more complex the project, the more likely there will be multiple cross-cutting elements. As a rule, all projects have “Project Management” as one of the cross-cutting elements.

Cross-cutting elements often involve secondary or intermediate deliverables such as analytical reports that support the product deliverables. Where data deliverables that support the primary hardware (or software) product deliverable exist, they are frequently identified as a subdivision or work package under a cross-cutting element.

Analysis of many different WBSs identifies four types of cross-cutting elements:

Integrative

Analytical

Process

Project Management

The first three can occur at Level 2 or any lower level of the WBS, but Project Management is normally a Level 2 element. (It is important to note that Level 1 is defined as the top level, as shown in Figure 2-4.)

An Integrative element represents work that integrates two or more peer WBS elements. This is shown graphically in Figure 2-7 in the “Assembly” element.

FIGURE 2-7 Example of WBS with Integrative Element

In the simplified example in Figure 2-7, the product breakdown of the bicycle includes the frame, seat, pedals and gears, and handlebars. The “Assembly” work element is integrative because it represents the work involved in combining the other four elements—it integrates them. The Assembly work element—or its equivalent—is often missed when first developing a WBS or is implicitly assumed to be work that is part of the next higher or parent element. This false assumption violates the 100 percent rule that states the sum of the work of the elements at a child level is 100 percent of the parent.

The work flows from the other WBS peer elements to the integrative element.

Figure 1-6 also includes the integration WBS element Assembly at Level 4 under the Level 3 “Wall” element.

An Analytical Element represents analytical activity that spans the work elements of a common parent. This is shown graphically in Figure 2-8 in the sample WBS for a project that included development of a personal computer.

FIGURE 2-8 Example of WBS with Analytical Element

In the preceding example, “System Analyses” is a cross-cutting analytical element in the WBS. This element cuts across all the work in the other elements at the same level and below in the WBS. The system analyses affect the development and content of the other WBS elements. Information flows from the analytical element to the other elements and impacts their design, development, or content. If the project were for writing a book or preparing a report, a WBS element “Research” at Level 2 would be another analytical-type element, with the information flowing from the research work performed to affect the contents of the other elements of the book.

The next level of decomposition below an analytical element is often a set of work elements that are of a similar type as the parent, such as occurs in a parent element in a service project. For example, the next level below a System Engineering element may be a group of similar engineering functions, such as Reliability Engineering, Maintainability Engineering, Value Engineering, and the like. The outputs of these functions are often data deliverables such as a Reliability Plan or a Reliability Analysis, and they would be specified in the contract SOW or a contract data requirements list.

The Level 2 element may be even more general, such as just “Analyses,” and would include such items as “Needs Analysis,” “Economic Analysis,” and “Demand Analysis,” depending on the nature of the project. This type of element is similar to the elements in a service project and represents a grouping of similar or related work that is necessary for the project.

A Process element represents a next step in a work progression. It is similar to an Integrative element but is more related to the flow of work than the grouping or combination of several elements. This is shown graphically in Figure 2-9.

FIGURE 2-9 Example of WBS with Process Element

The WBS element Test and Evaluation is cross-cutting and is also the next step in a development process. At the level shown in the figure, the work performed in the Test and Evaluation element “cuts across” the other elements at the same level, its peers, and would require manuals, support equipment, the air vehicle (airplane), and maintenance facilities to do the testing work. The work flows into the direction of the process. Note that the other four Level 2 items are product deliverables.

In Figure 2-10, “System Test” is a process element because it is the next step in the process of preparing a PC for delivery to the customer. The work flows along the steps in the process. Also, the shaded work packages of the parent “Circuit Boards” are all process WBS elements leading to the intermediate deliverable of “Circuit Boards.”

FIGURE 2-10 Example of WBS with Process Elements

Project Management Element

While all WBSs have one or more of the first four types of WBS elements (product, service, results, and cross-cutting), all four do not always occur in every WBS. However, “Project Management” is a special category of cross-cutting element that occurs universally and can have characteristics of the integrative, analytical, or process elements within it at lower levels. While all WBSs have one or more of the first four types of WBS elements, they do not always occur in every WBS. The reason is that all projects have project managers, and they perform various types of work in support of the project.

The 100 percent rule requires the sum of the WBS elements at each level to represent 100 percent of the work of the parent. Because the project manager expends resources, work is involved and must be included. The labor cost and other expenses of the project manager and the Project Management Office may or may not be charged to the project as a direct cost, but resources are consumed, and project management activities are performed.

FIGURE 2-11 Project Management WBS Element Decomposition

Figure 2-11 contains a listing of typical Level 3 WBS elements contained in “Project Management.” Level 4 in Figure 2-11 consists mostly of work packages. The exceptions are the two zero-duration activities, Contract Award and Complete Project, which are useful milestones to have in schedules. The advantages of their inclusion in this list and their usage are explained later in this chapter in the section titled “Numbering the WBS.”

Frequently, some of the Level 4 items listed in the figure are routinely furnished by the parent organization and may not appear in the project WBS. In addition, some items may warrant their own Level 3 or Level 2 status if there is a significant amount of work to perform and it is deemed important to focus attention on it through the WBS. In any event, if work and resources are involved in any of the elements, those resources and the work should be reflected in the project plans. In addition, one of the rules of planning is to include the item in a plan if it will not automatically be performed.

The 100 percent rule applies to all the work at Levels 3 and 4, and all important work packages or activities must be included. The planning and resource allocations must address the large amount of work involved in managing a project.