Project Management: Establishing a Work Breakdown Structure, Part 228 April 2015

Project Management

This article is the completion of a blog published in March which discussed the third critical step necessary for a successful program. The March blog, titled Project Management: Establishing a Work Breakdown Structure, focused on the preparation of a work breakdown structure (WBS) which serves as the foundation for a Final Program Baseline.

This article will continue the discussion of a program WBS by providing examples of WBS tasks. It will also discuss the importance of developing the critical path for a program and provide some best practices to be used in the development of the WBS.

The simplified functional WBS drawing below was provided in the March blog and illustrates how a WBS should be structured to address the phases, work categories and levels of task detail for a typical program.

Chart: Work Breakdown System

What types of tasks should be included in a WBS?
To the maximum extent possible, every task required to design, develop, test, produce, install, and operate a system or service should be included in the program WBS. The accuracy of the cost and schedule estimates for a program decreases with each task that is not included in the program WBS. As stated in the first part of this blog, it is extremely difficult, if not impossible, to specify or define every task that should or should not be included in the overall WBS for a program. A few high-level examples of the many types of tasks that should be included for each major phase of a program are:

Acquisition Planning

  • Preparation of acquisition strategy plan
  • Preparation of contract documents (e.g., system specification, statement of work, contract data requirements, data item descriptions, etc.)
  • Preparation of contract selection documents (e.g., technical and cost proposal evaluation plans, source selection plan, single source justification if applicable, etc.).
  • Evaluation of cost and technical proposals
  • Oral presentations if used in the contract selection process
  • Conduct of prototype demonstrations if used in the contract selection process
  • Preparation of cost and technical proposal evaluation reports and source selection report


  • Preparation of all applicable contract program, cost, system technical design, and reporting documents required by the contract (e.g., program plan, configuration management plan, risk management plan, periodic contract reports, all hardware, software, and system interface design documents, etc.)
  • Fabrication of system prototypes or pre-production systems or units to be used for early proof of concept and qualification tests
  • Preparation of all test and evaluation plans and reports required for contractor, user, and independent tests
  • Preparation of all installation plans, guidance and schedules necessary to install and checkout the systems or service
  • Preparation of training courses as required

Test & Evaluation (T&E)

  • Conduct of all T&E (including regression testing for redesign and retesting)
  • Preparation of reports documenting the results of T&E tests


  • Installation of the system or service
  • Conduct of the installation and checkout tests
  • Modification of any other systems affected by your system or project

Lifecycle Operation and Maintenance

  • Periodic hardware and software changes
  • Replacement of spare parts and test equipment
  • Changes in operator and maintenance training courses

What is a critical path?
Another important use of the WBS and schedule estimates for each WBS task is to support the development of the “critical path” for the program. The critical path of a program is defined as the succession of all program tasks that are connected and will take the longest period of time to complete.

Another way of saying it is that the critical path is the longest period of time it will take to achieve the end state of the project. A “predecessor” and “successor” must be identified for each WBS task in order to “connect” each related task and develop the critical path for the program. Many tasks in a project may not be on the critical path because they can be accomplished within the longer schedule of other program tasks that are being performed at the same time. The schedule for tasks that are not on the critical path is referred to as a “float” or “slack” in a project schedule.

What are some best practices for preparing a WBS?
Some best practices to follow when preparing a WBS for a program include:

  • Each task involving the preparation of documents should include all steps or sub-tasks required to prepare, review, change and approve each document. Never assume the first version of a document will be approved – it just doesn’t happen. In fact, multiple revision cycles may be required for many documents and other tasks before they are approved or finalized.
  • Realistic or low risk schedule estimates should be used for each task unless the program has a high priority or urgency and the procuring agency or company is willing to accept the risk of the base-lined schedules not being achieved.
  • Ensure that all tasks have been identified. Having an external or independent source review your draft WBS is highly recommended to ensure all necessary tasks have been included and realistic schedule estimates have been assigned to each task. Other ways to reduce program risks are to perform a thorough comparison of your WBS and list of required program documents with your government/company acquisition requirements. Another risk reduction tactic is to compare the WBS and cost and schedule estimates for your project with the WBS and actual cost and schedule values of other similar projects that have been previously accomplished.
  • Perhaps the most critical part of a program WBS is that it must include every work task on the critical path of a program.

What are the challenges in preparing a WBS and cost and schedule estimates?
There are many challenges in preparing a high quality WBS and cost and schedule estimates for a major program. Some examples of challenges that will be encountered are:

  • Identifying all of the significant tasks required to execute a major program
  • Estimating the time and cost for each of the tasks with high accuracy
  • Identifying risk areas and addressing them appropriately in the cost and schedule estimates
  • Preparing a highly accurate and complete WBS and cost and schedule estimates in a short period of time

Who should prepare a WBS and cost and schedule estimates?
Many types of subject matter experts are typically required to prepare a WBS and cost and schedule estimates for a major program, including the following:

  • Program managers ensure that all necessary work tasks, cost estimates and schedule estimates are properly developed that conform to acquisition regulations and requirements
  • Engineers are responsible for all engineering and technical work tasks (e.g., hardware, software, interface, reliability, maintainability, human factors, safety, etc.) and cost and schedule estimates for them
  • Logistics support ensures that all life cycle support requirements (e.g., training, maintenance, parts support, etc.) are properly identified and that cost and schedule estimates for each logistics element are properly developed
  • Business/financial support the development of cost estimates, provide guidance for budget and financial processes that must be followed
  • Contract experts are responsible for the preparation and management of all contracts required for the program
  • Operational experts are responsible for supporting the identification of all operation-related tasks and supporting the development of cost and schedule estimates for them

In summary, developing a complete WBS and accurate cost and schedule estimates for a major program is extremely difficult. This two-part blog is intended to provide a high level glimpse into the effort required to establish the final cost, schedule and performance baseline for a program. For a deeper conversation about any of the first three critical tasks we’ve discussed so far, feel free to contact us.

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