Work breakdown structure (WBS): the spine of an integrated plan
A work breakdown structure lists everything the project must deliver, split into pieces small enough to plan, price and own. It is the spine of an integrated plan.
These are the eight planning threads the Krong course is built around. The highlighted ones are covered here. What are the planning threads?
How a WBS is built
Start with the project outcome. Split it into a few components. Split each component into work packages. Stop when a package can be estimated, assigned to one team and checked as done.
Give every item an ID such as 1.3.2. Those IDs are the real prize. They let every other part of the plan point to the same piece of work.
Caldera Freight: nine components, 35 work packages
| ID | Component | Budget (USD) |
|---|---|---|
| 1.1 | Project planning and requirements definition | 180,000 |
| 1.2 | Data acquisition and preparation | 380,000 |
| 1.3 | Route optimisation platform development | 650,000 |
| 1.4 | Driver mobile application implementation | 360,000 |
| 1.5 | Pilot deployment and validation | 200,000 |
| 1.6 | Full operational deployment | 150,000 |
| 1.7 | Training and organisational change management | 320,000 |
| 1.8 | Monitoring and performance reporting system | 100,000 |
| 1.9 | Post-implementation evaluation | 60,000 |
| Total | 2,400,000 |
The nine components add up to the approved budget. That check is the 100 per cent rule: the pieces must equal the whole, with nothing missing and nothing extra.
Which level holds the budget
Count the levels from the top. Level 1 is the whole project, with one total budget. Level 2 is the components, such as 1.3. Level 3 is the work packages, such as 1.3.2.
A bottom-up estimate prices the lowest level, the work packages, and adds them up: packages make a component, components make the project. The work package budgets are the ones that count. A component budget typed by hand is only a shortcut and can drift away from them.
In Sen, give every work package a budget on the Budget and EVM tab. Then, on the Risk and contingency tab, set Component budgets come from to the sum of each component's task budgets. The component figures, and the way the contingency reserve is shared, then follow the work packages.
Why the IDs matter for integration
Once work package 1.3.2, Model development and testing, exists, the rest of the plan can attach to it.
- Time: it lasts 8 weeks and follows 1.3.1.
- Money: it has a budget of USD 216,700 in the earned value baseline.
- People: the Optimisation Engineering Team is responsible, and the Project Manager is accountable.
- Uncertainty: risks such as R-03, algorithms that may not achieve the expected efficiency, point to its component, 1.3.
Common mistakes
- Writing activities as nouns in one place and verbs in another. Pick one style.
- Going too deep. A package of two to ten weeks is usually enough.
- Leaving out management work, training or handover. They cost money and take time.
- Changing the IDs later. Every link then breaks.
How Sen helps
In Sen, the Schedule tab owns the WBS. The RACI matrix, the risk register, the KPI activities and the earned value table all use the same IDs. Add a task once and it shows up in each of them.
Questions people ask
What is a work breakdown structure?
A WBS is a hierarchy that splits a project into components and work packages so each piece can be scheduled, costed and owned.
How detailed should a WBS be?
Detailed enough that each work package can be estimated and assigned to one team. For many projects, packages of two to ten weeks work well.
What is the 100 per cent rule?
The components of a WBS must add up to the whole project scope and budget, with nothing missing and nothing double counted.
See it in a real plan
Open Sen and explore the Caldera Freight example. Every figure on this page comes from it. Copy it, change a task, and watch the plan move together.
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