“Work Breakdown Structure (WBS) is a deliverable-oriented grouping of work.” Project Management Body ofKnowledge (PMBOK), Version 6.
When starting a project from ground zero, the planner (very often the project manager himself) may grope around in the dark for a while without knowing where to start. A Work Breakdown Structure (WBS) is the answer.
One starts by envisaging the high-level deliverables of the project and derives the high-level work breakdown structure (WBS), which gets elaborated further into detailed WBS, and then to activities and schedule.
WRENCH has studied deeply how to construct a good quality WBS as part of their Project Health Management technology solution, and I am working with them now to develop an information package that will help project professions understand the critical role that IT plays in assessing and controlling the health of a construction project.
A well-developed WBS provides clarity of scope and improved estimates. Even after years of being in this field I never quite realized the sheer amount of work involved when you start thinking of monitoring and progress data not just as data, but as symptoms and signs linked to the project’s overall ‘health’. With this shift in perspective (ie from trying to collectively analyse ALL the performance data in order to derive the project’s performance status to filtering out ONLY the exceptions and deviations which signal ‘ill health’), came the epiphany that most project managers are actually drowning in information overload – they don’t need more data, they need usable data. They don’t need to know what all is going right, they need to know only what’s going wrong. They need a way to quickly identify potential ‘heath problems’ and nip them in the bud without wading through hundreds or thousands of pages of reports. Without a WBS, definitive estimates within +-5% accuracy levels is impossible.
The WBS is a great tool for explaining the scope of work to other key stakeholders. It is designed for real life projects where there are several interdisciplinary teams working concurrently. Errors and omissions in any WBS can be a very expensive price of non conformance (PONC), which surfaces during construction or commissioning phase, and that is something WRENCH factored in.
What is a Work Breakdown Structure (WBS)?
Ever since the first WBS was developed by United States Department of Defence (DoD) in 1962, it has become the essential component of every project management framework (PMBOK, PRINCE, TCM). A WBS is the heart of the project management system. WBS is closely linked into project scope & execution strategy development, and project control plan implementation. A WBS can make or break the project, in other words.
Based on the project domain, disciplines and purpose there are different flavours of work breakdown structures;
- Contract work breakdown structure (CWBS), A work breakdown structure of the
products or services to be furnished under contract. It is comprised of selected PWBS (program / project WBS) elements specified in the contractual document and the contractor’s lower level extensions of those elements.
- Project work breakdown structure (PWBS), a summary level WBS, used by the senior management, also referred as WBS.
- Engineering work breakdown structure – Prepared by the engineering discipline
- Construction work breakdown structure – Detailed work breakdown structure prepared by the construction discipline
- Installation work breakdown structure – Detailed work breakdown structure for the implementation team
Reasons for poor quality of WBS – Nomar E.S (2005)
- No literature available about developing quality WBS
- Many believe that they have done a good quality WBS, but all they have done is listing of activities
- Scheduling tool builds the WBS as one keys in activities
- Many organizations encourage to skip the development of deliverable-oriented WBS, in a rush to get the project started
WBS design principles
- 100% rule – WBS must cover the entire scope of work. Whatever is not there in the WBS will not be there in the final product. Enough care must be taken to ensure scope coverage. We have successfully tried Delphi technique in the development of the critical areas of WBS. We explained the scope of work to different teams, and they developed WBS independently and then we merged them together to arrive at the best, thus ensuring scope coverage and quality. High quality WBS creation needs good teamwork across all relevant stakeholders, as there is no single person who knows everything.
- Mutual exclusivity – Must ensure that there is no redundancy of work in the WBS
- Plan outcomes, not activities – WBS is a deliverable-oriented grouping of work. Deliverables and milestones are not one and the same.Milestones are just major events in the project, and need not be always associated with deliverables. All deliverables need not be milestones and vice-versa.
- 8-80 rule – Work packages (the lowest level in the WBS), must be between 8 hours and 80 hours of work. For small projects, the affinity of the work packages should be towards 8 hours whereas for large projects the affinity of the work packages must be towards 80 hours. Smaller projects having large work packages and large projects having smaller work packages will scuttle project progress monitoring and risk management. Project sizing and work package sizing is very important.
- Activity durations must be less than the reporting period
- Minimum 3 levels – WBS should have minimum three levels. In our example above (Project health assessment and control), we have three levels, which is the minimum. As the size and complexity of the projects increases, so do the levels in the WBS.
- Tree or List – Work breakdown structures can be represented as a tree structure or as a list.
WBS Dictionary – Example – Provides additional information about the work packages
I am quite impressed with the Wrench project management tool’s ability to create work breakdown structures of any number of levels. This enables the users to drill down to task level and at the same time roll up to project or program levels, with ease.
I hope this was helpful. Please share your feedback in the comments or any questions you may have.
See you soon!
References
Total Cost Management framework by AACE
Project Management Body of Knowledge (PMBOK) by PMI, USA
Wrench Academy 