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Broad Contents


Characteristics of various levels of Work Breakdown Structure (WBS)

Characteristics of Work Package

Guidelines for Work Breakdown Structure (WBS) by Contractor

Criteria for Developing Work Breakdown Structure (WBS)

Work Breakdown Structure (WBS) Decomposition Problems

Uses of Work Breakdown Structure (WBS)

22.1 Introduction:

In order to successfully accomplish both contract and corporate objectives, a plan is required

that defines all effort to be expended, assigns responsibility to a specially identified

organizational element, and establishes schedules and budgets for the accomplishment of the

work. The preparation of this plan is the responsibility of the program manager, who is assisted

by the program team assigned in accordance with program management system directives. The

detailed planning is also established in accordance with company budgeting policy before

contractual efforts are initiated.

Keeping this in view, in planning a project, the project manager must structure the work into

small elements that are:

  • Manageable, in that specific authority and responsibility can be assigned
  • Independent, or with minimum interfacing with and dependence on other ongoing elements
  • Integratable so that the total package can be seen
  • Measurable in terms of progress

After project requirements definition, the first major step in the planning process is the

development of the Work Breakdown Structure (WBS). A Work Breakdown Structure (WBS)

is a product-oriented family tree subdivision of the hardware, services, and data required to

produce the end product. The Work Breakdown Structure (WBS) is structured in accordance

with the way the work will be performed and reflects the way in which project costs and data

will be summarized and eventually reported. Preparation of the Work Breakdown Structure

(WBS) also considers other areas that require structured data, such as scheduling, configuration

management, contract funding, and technical performance parameters. It is the single most

important element because it provides a common framework from which:

  • Total program can be described as a summation of subdivided elements
  • Planning can be performed
  • Costs and budgets can be established
  • Time, cost, and performance can be tracked
  • Objectives can be linked to company resources in a logical manner
  • Schedules and status-reporting procedures can be established
  • Network construction and control planning can be initiated
  • Responsibility assignments for each element can be established

Note that the Work Breakdown Structure (WBS) acts as a vehicle for breaking the work down

into smaller elements, thus providing a greater probability that every major and minor activity

will be accounted for.

Although a variety of Work Breakdown Structure (WBS) exist, the most common is the sixlevel

indented structure shown as Figure 22.1 below:

Six-Level Indented Structure

As the figure shows, Level 1 is the total program and is composed of a set of projects. The

summation of the activities and costs associated with each project must equal the total program.

Each project, however, can be broken down into tasks, where the summation of all tasks equals

the summation of all projects, which, in turn, comprises the total program. The reason for this

subdivision of effort is simply ease of control. Program management therefore, becomes

synonymous with the integration of activities, and the project manager acts as the integrator,

using the work breakdown structure as the common framework.

It is important that careful consideration must be given to the design and development of the

Work Breakdown Structure (WBS). It can be used to provide the basis for the following:

Work Breakdown Structure (WBS) for Objective Control and Evaluation

  • Responsibility matrix
  • Network scheduling
  • Costing
  • Risk analysis
  • Organizational structure
  • Coordination of objectives
  • Control (including contract administration)
22.2 Characteristics of Various Levels of the Work Breakdown Structure (WBS):

As depicted in Figure 22.1 (above), the upper three levels of the Work Breakdown Structure

(WBS) are normally specified by the customer (if part of a Request for Proposal (RFP)/Request

for Quotation (RFQ) (i.e. RFP/RFQ) as the summary levels for reporting purposes. The lower

levels are generated by the contractor for in-house control. Each level serves a vital purpose:

Level 1 is generally used for the authorization and release of all work, budgets are prepared at

level 2, and schedules are prepared at level 3. Certain characteristics can now be generalized for

these levels:

Firstly, The top three levels of the Work Breakdown Structure (WBS) reflect integrated

efforts and should not be related to one specific department. Effort required by departments

or sections should be defined in subtasks and work packages.

The summation of all elements in one level must be the sum of all work in the next lower


Each element of work should be assigned to one and only one level of effort. For example,

the construction of the foundation of a house should be included in one project (or task), not

extended over two or three. (At level 5, the work packages should be identifiable and


The level at which the project is managed is generally called the work package level.

Actually, the work package can exist at any level below level one.

The Work Breakdown Structure (WBS) must be accompanied by a description of the scope

of effort required, or else only those individuals who issue the Work Breakdown Structure

(WBS) will have a complete understanding of what work has to be accomplished. It is

common practice to reproduce the customer's statement of work as the description for the

Work Breakdown Structure (WBS).

It is often the best policy for the project manager, regardless of his technical expertise, to

allow all of the line managers to assess the risks in the Work Breakdown Structure (WBS).

After all, the line managers are usually the recognized experts in the organization.

It is normally the duty of the project managers to manage at the top three levels of the Work

Breakdown Structure (WBS) and they prefer to provide status reports to management at these

levels also. Some companies are trying to standardize reporting to management by requiring the

top three levels of the Work Breakdown Structure (WBS) to be the same for every project, the

only differences being in levels 4–6. For companies with a great deal of similarity among

projects, this approach has merit. For most companies, however, the differences between

projects make it almost impossible to standardize the top levels of the Work Breakdown

Structure (WBS).

As shown in the Figure 22.1 (above), the work package is the critical level for managing a

Work Breakdown Structure (WBS). However, it is possible that the actual management of the

work packages are supervised and performed by the line managers with status reporting

provided to the project manager at higher levels of the Work Breakdown Structure (WBS).


To explain them further, work packages are natural subdivisions of cost accounts and constitute

the basic building blocks used by the contractor in planning, controlling, and measuring contract

performance. A work package is simply a low-level task or job assignment. It describes the

work to be accomplished by a specific performing organization or a group of cost centers and

serves as a vehicle for monitoring and reporting progress of work. Documents that authorize

and assign work to a performing organization are designated by various names throughout


Here, it is important to know what a work package is. "Work package" is the generic term used

in the criteria to identify discrete tasks that have definable end results. Ideal work packages are

80 hours and less than 2–4 weeks. However, this may not be possible on large projects.

It is not necessary that work package documentation contain complete, stand-alone descriptions.

Supplemental documentation may augment the work package descriptions. However, the work

package descriptions must permit cost account managers and work package supervisors to

understand and clearly distinguish one work package effort from another. In the review of work

package documentation, it may be necessary to obtain explanations from personnel routinely

involved in the work, rather than requiring the work package descriptions to be completely selfexplanatory.

The cost account intersection

The desirability of having short-term work packages is a key feature from the standpoint of

evaluation accomplishment. This requirement is not intended to force arbitrary cutoff points

simply to have short-term work packages. Work packages should be natural subdivisions of

effort planned according to the way the work will be done. However, when work packages are

relatively short, little or no assessment of work-in-process is required and the evaluation of

status is possible mainly on the basis of work package completions. The longer the work

packages, the more difficult and subjective the work-in-process assessment becomes unless the

packages are subdivided by objective indicators such as discrete milestones with pre-assigned

budget values or completion percentages.

Keeping this in view, in setting up the Work Breakdown Structure (WBS), tasks should:

  • Have clearly defined start and end dates
  • Be usable as a communications tool in which results can be compared with expectations
  • Be estimated on "total" time duration, not when the task must start or end
  • Be structured so that a minimum of project office control and documentation (that is, forms) is necessary

22.3 Characteristics of Work Package:

In case of large projects, planning will be time phased at the work package level of the Work

Breakdown Structure (WBS). The work package has the following characteristics:

  • Represents units of work at the level where the work is performed
  • Clearly distinguishes one work package from all others assigned to a single functional group
  • Contains clearly defined start and end dates that are representative of physical accomplishment
  • Specifies a budget in terms of dollars, man-hours, or other measurable units
  • Limits the work to be performed to relatively short periods of time to minimize the work-in
  • process effort

The following table (table 22.1) shows a simple Work Breakdown Structure (WBS) with the

associated numbering system following the work breakdown. The first number represents the

total program (in this case, it is represented by 01), the second number represents the project,

and the third number identifies the task. Therefore, number 01-03-00 represents project 3 of

program 01, whereas 01-03-02 represents task 2 of project 3. This type of numbering system is

not standard; each company may have its own system, depending on how costs are to be


Work Breakdown Structure (WBS) for New Plant Construction and Start-Up

By now we can say that the preparation of the work breakdown structure is not easy. The Work

Breakdown Structure (WBS) is a communications tool, providing detailed information to

different levels of management. If it does not contain enough levels, then the integration of

activities may prove difficult. If too many levels exist, then unproductive time will be made to

have the same number of levels for all projects, tasks, and so on.

It is vital that each major work element should be considered by itself. Remember, the Work

Breakdown Structure (WBS) establishes the number of required networks for cost control.

In case of many programs, the customer establishes the Work Breakdown Structure (WBS).

22.4 Guidelines for WBS by Contractor:

To explain this, we take the example of a contractor who is required to develop a Work Breakdown

Structure (WBS). He must consider certain guidelines. A partial list is as follows:

  • Complexity and technical requirements of the program (i.e., the statement of work)
  • Program cost
  • Time span of the program
  • Contractor's resource requirements
  • Contractor's and customer's internal structure for management control and reporting
  • Number of subcontracts

Remember that applying these guidelines serves only to identify the complexity of the program.

These data must then be subdivided and released, together with detailed information, to the different

levels of the organization. The Work Breakdown Structure (WBS) should follow specified criteria

because, although the program office performs preparation of the Work Breakdown Structure

(WBS), the actual work is performed by the doers, not the planners. Both the doers and the planners

must be in agreement as to what is expected.

22.5 Criteria for Developing Work Breakdown Structure (WBS):

Following is a sample listing of criteria for developing a Work Breakdown Structure (WBS):

The Work Breakdown Structure (WBS) and work description should be easy to understand.

All schedules should follow the Work Breakdown Structure (WBS).

No attempt should be made to subdivide work arbitrarily to the lowest possible level. The

lowest level of work should not end up having a ridiculous cost in comparison to other


Since scope of effort can change during a program, every effort should be made to maintain

flexibility in the Work Breakdown Structure (WBS).

The Work Breakdown Structure (WBS) can act as a list of discrete and tangible milestones

so that everyone will know when the milestones were achieved.

Level of the Work Breakdown Structure (WBS) can reflect the "trust" you have in certain

line groups.

Work Breakdown Structure (WBS) can be used to segregate recurring from nonrecurring


Most Work Breakdown Structure (WBS) elements (at the lowest control level) range from

0.5 to 2.5 percent of the total project budget.


22.6 Work Breakdown Structure (WBS) Decomposition Problems:

Misconceptions prevail with almost every thing. There is a common misconception that the

Work Breakdown Structure (WBS) decomposition is an easy task to perform. In the

development of the Work Breakdown Structure (WBS), the top three levels or management

levels are usually roll-up levels.

Preparing templates at these levels is becoming common practice. However, at levels 4–6 of the

Work Breakdown Structure (WBS), templates may not be appropriate. There are the following

reasons for this:

Firstly, breaking the work down to extremely small and detailed work packages may require

the creation of hundreds or even thousands of cost accounts and charge numbers. This could

increase the management, control, and reporting costs of these small packages to a point

where the costs exceed the benefits. Although a typical work package may be 200–300

hours and approximately two weeks in duration, consider the impact on a large project,

which may have more than one million direct labor hours.

Breaking the work down to small work packages can provide accurate cost control if, and

only if, the line managers can determine the costs at this level of detail. Line managers must

be given the right to tell project managers that costs cannot be determined at the requested

level of detail.

The Work Breakdown Structure (WBS) is the basis for scheduling techniques such as the

Arrow Diagramming Method and the Precedence Diagramming Method. At low levels of

the Work Breakdown Structure (WBS), the interdependencies between activities can

become so complex that meaningful networks cannot be constructed.

To cater to the above-mentioned problems, one solution is to create "hammock" activities,

which encompass several activities where exact cost identification cannot or may not be

accurately determined. Some projects identify a "hammock" activity called management support

(or project office), which includes overall project management, data items, management

reserve, and possibly procurement. The advantage of this type of hammock activity is that the

charge numbers are under the direct control of the project manager.

In addition to this, there is a common misconception that the typical dimensions of a work

package are approximately 80 hours and less than two weeks to a month. Although this may be

true on small projects, this would necessitate millions of work packages on large jobs and this

may be impractical, even if line managers could control work packages of this size.

Cost analysis down to the fifth level is advantageous, from a cost control point of view.

However, it should be noted that the cost required to prepare cost analysis data to each lower

level might increase exponentially, especially if the customer requires data to be presented in a

specified format that is not part of the company's standard operating procedures. The level-5

work packages are normally for in-house control only. Some companies bill customers

separately for each level of cost reporting below level 3.

Another aspect is that the Work Breakdown Structure (WBS) can be subdivided into sub

objectives with finer divisions of effort as we go lower into the Work Breakdown Structure

(WBS). By defining sub objectives, we add greater understanding and, it is hoped, clarity of

action for those individuals who will be required to complete the objectives. Whenever work is

structured, understood, easily identifiable, and within the capabilities of the individuals, there

will almost always exist a high degree of confidence that the objective can be reached.

Also, the Work Breakdown Structure (WBS) can be used to structure work for reaching such

objectives as lowering cost, reducing absenteeism, improving morale, and lowering scrap


factors. The lowest subdivision now becomes an end-item or sub-objective, not necessarily a

work package as described here.

Since we are describing project management, therefore, for the remainder of the text we will

consider the lowest level as the work package.

22.7 Uses of Work Breakdown Structure (WBS):

It is important to remember that once the Work Breakdown Structure (WBS) is established and the

program is "kicked off," it becomes a very costly procedure to either add or delete activities, or

change levels of reporting because of cost control. Many companies do not give careful forethought

to the importance of a properly developed Work Breakdown Structure (WBS), and ultimately they

risk cost control problems downstream. One important use of the Work Breakdown Structure

(WBS) is that it serves as a cost control standard for any future activities that may follow on or may

just be similar. One common mistake made by management is the combining of direct support

activities with administrative activities. For example, the department manager for manufacturing

engineering may be required to provide administrative support (possibly by attending team

meetings) throughout the duration of the program. If the administrative support is spread out over

each of the projects, a false picture is obtained as to the actual hours needed to accomplish each

project in the program. If one of the projects should be canceled, then the support man-hours for the

total program would be reduced when, in fact, the administrative and support functions may be

constant, regardless of the number of projects and tasks.

It is quite often that the Work Breakdown Structure (WBS) accompanying customer Request for

Proposals (RFPs), contains much more scope of effort as specified by the statement of work than the

existing funding will support. This is done intentionally by the customer in hopes that a contractor

may be willing to ''buy in." If the contractor's price exceeds the customer's funding limitations, then

eliminating activities from the Work Breakdown Structure (WBS) must reduce the scope of effort.

By developing a separate project for administrative and indirect support activities, the customer can

easily modify his costs by eliminating the direct support activities of the canceled effort.

Lastly, we should also discuss the usefulness and applicability of the Work Breakdown Structure

(WBS) system. Many companies and industries have been successful in managing programs without

the use of work breakdown structures, especially on repetitive-type programs.

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