What’s a WBS Dictionary, and Do I Need One?

A big reason projects with technical deliverables fail is that the PM and team assume everyone understands the deliverables and what it takes to deliver them. A Work Breakdown Structure (WBS) Dictionary can be a lifesaver in that case. Here is a review of what’s in a WBS Dictionary, along with tips for when it’s needed (or not).

A WBS Dictionary focuses on providing detailed information on each work package in a WBS, including:

• • A description
  • Deliverables and acceptance criteria
  • Key dependencies and assumptions
  • Budget estimates or resource and skill needs
  • Constraints or boundaries, focusing on what each work package doesn’t include

Take the time to develop a WBS Dictionary when:

• The project requires multiple teams or handoffs. Any time work passes through several groups, such as engineering to procurement or procurement to a vendor, a WBS dictionary helps prevent assumptions from derailing the timeline. If even one team needs clarification on scope, deliverables, or boundaries, developing a WBS Dictionary is worth it.
• Work packages are complex or technical. Whenever tasks could be interpreted in multiple ways, such as specialized information technology work, regulatory steps, or integration tasks, a dictionary protects the project from ambiguity. It provides teams with detailed descriptions, constraints, deliverable definitions, and acceptance criteria, so no one fills in the gaps with assumptions.
• Vendor or contract work is involved. If external suppliers provide any part of a project solution, a WBS dictionary helps align the project’s needs with the vendor contract. It provides procurement and vendors with a shared definition of “done” and reduces the headaches and costs associated with change orders.

You can save time by not creating a WBS Dictionary when: 

• Managing a small or tightly scoped project. If you’re working on a project where team members know each other and are intimately familiar with the tasks and technologies they will use, maintaining a complete WBS dictionary adds bureaucracy. A straightforward, agreed-upon WBS should provide sufficient clarity.
• Project risk is low and is easy to address. The extra effort to create a WBS Dictionary is worthwhile when significant risk is present. For a low-risk project, it can become just one more thing that takes time and ends up sitting in a file cabinet collecting dust. In many cases, a few work packages where risk lies in the project need WBS Dictionary entries.

 

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