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- 30 Mar 2019
The importance of a good Work Breakdown Structure
Without a good work breakdown structure, an accurate estimate of the project is impossible. All definitive estimates demands an estimation accuracy percentage ranging between -2 to +2 percentage, and it is impossible to achieve this kind of estimation accuracy without a good quality work breakdown structure. While 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 and end the planning process. The first and foremost step is to understand the scope of the project and the product, in-order to decompose them into a good quality work breakdown structure, the basis for further planning, monitoring and controlling of the project.
The starting point
Developing Work Breakdown Structure (WBS) of the project is the best starting point. Deliverable oriented grouping of project’s work is the work breakdown structure. For some projects, the work breakdown structure is provided along with the contract documentation. In such cases check for the level of detailing. If needed, detail it to the desired level if required. Project scope and contract documentation comes in handy while developing work breakdown structure.
Project’s scope can be baselined when there is sufficient confidence on the WBS. One start by envisaging the high level deliverables to develop the high level WBS. Further elaboration of the high level WBS results in the detailed WBS. As you can see, WBS is the basis for all further planning, including the schedule of the project. What is not there in the WBS will not be there in the final product / deliverable of the project. Hence ensuring scope coverage of the WBS is very important.
WRENCH solutions 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.
Management by exceptions
A well-developed WBS provides clarity of scope and improved estimates. Work breakdown structures must support progress monitoring. Even after years of being in this field, I never quite realized the increased effectiveness of project management, when you start thinking of monitoring 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. All 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.
The WBS is a great tool for explaining the scope of work to other key stakeholders. Communicating the scope with clarity is a challenge especially when interdisciplinary teams work in the project concurrently. I have found work breakdown structure as a effective tool for communicating scope with clarity to the relevant stakeholders. The effort spent in developing good work breakdown structures can be easily justified by the reduction in errors and omissions, a very expensive price of non conformance (PONC), when surfaced during construction or commissioning phases.
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.
Different types of Work breakdown structures
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. They are also known as Product Breakdown Structure (PBS).
- 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. This bottom up approach can lead to missing out of certain work packages altogether.
- Sometimes , organizations encourage to skip the development of deliverable-oriented WBS, in a rush to get the project started
WBS design principles
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 all the scope is captured in the work breakdown structure. 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.
One must ensure that there is no redundancy of work in the WBS
Deliverable oriented grouping
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.
Decomposing the scope into work packages (the lowest level in the WBS) delivers the work breakdown structure. The lowest level in the work breakdown structure is considered as the work package. During decomposition of the scope into work breakdown structure, what is the right level of decomposition?. The 8-80 rule suggests that the Work packages must be between 8 hours and 80 hours of chunks 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 for effective project control and monitoring.
The duration of the activities within the reporting period 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.
Work breakdown structures can be represented as a tree structure or as a list structure. Which structure to use to represent the WBS is decided by the comfort level of the stakeholders who uses them.
WBS Dictionary provides additional information about the work packages. The objective of the work breakdown dictionary is to provide sufficient information to the person who will be working on the work package, so that he has sufficient clarity to perform the work correctly on time. There is no hard and fast rule about what should be part of the WBS dictionary. Generally WBS dictionaries include;
- Description of the work to be performed
- Successor / Predecessor details
- References to specifications etc.
Sample WBS dictionary
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!
Wrench Academy Course
Test your knowledge about work breakdown structures and earn a Badge
Characteristics of good work breakdown structures
Total Cost Management framework by AACE
Project Management Body of Knowledge (PMBOK) by PMI, USA
Abrachan Pudussery is domain expert in Project Management area and a seasoned trainer. He heads the Wrench Academy, and brings in deep domain expertise and a conviction about higher quality in project management training.
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