21 Jun 2024
Building stronger projects: the power of resource management
When is your WBS effective?
“Do you know what a WBS is?”
“Yes, a Work Breakdown Structure.”
“It is a tree that divides the project into parts.”
“You’ve got the acronyms right, there.
“And do you also know how and why we should make a WBS?”
Silence.
The above conversation happens in almost all our PM training courses. Many people know what a WBS is, but much less how to create the right WBS and why they should do this. Or shouldn’t they do it at all?
“Yes, a Work Breakdown Structure.”
“It is a tree that divides the project into parts.”
“You’ve got the acronyms right, there.
“And do you also know how and why we should make a WBS?”
Silence.
The above conversation happens in almost all our PM training courses. Many people know what a WBS is, but much less how to create the right WBS and why they should do this. Or shouldn’t they do it at all?
The essence of project management
To evaluate the effectiveness of a WBS, we first take a step back and look at the essence of project management: a project manager (PM) receives a mandate to deliver a project within its constraints. The PM oversees planning, steering and controlling all the work (= project scope) that needs to be done to fulfill this mandate.
To achieve control over the project, the PM divides the total project scope into so-called work packages.
What are work packages?
Work packages are discrete and manageable partitions of the project scope. They should have a clear scope, finite timing, clear deliverables and a responsible manager assigned.
Work packages are used to authorize work to team members (or work package managers). The authorized individual will be responsible to deliver the scope of the work package. The project manager will focus on authorizing, monitoring, closing work packages and managing the interfaces between them. A formal process to authorize work packages to team members was previously named as one of the solutions to the persistent field disconnect.
Distilling a list of well-defined work packages with accompanying work descriptions and assigned responsibilities is arguably the most important planning task for a PM.
A list, indeed.
The traditional Work Breakdown Structure
At first glance, breaking down the project work into work packages may appear to be exactly what a WBS does, but we believe that using a tree structure to break down scope sets an unneeded (two-dimensional) restriction to how work packages are defined.
The WBS’s focus on a top-down breakdown of the project scope, could potentially divert attention from the most valuable outcome of scope planning: the compilation of a comprehensive list of mutually exclusive and collectively exhaustive work packages.
Turning the WBS upside down
Instead of following a rigid, top-down structure, a more effective approach might be to focus on grouping work items into work packages from the bottom up. The key question in scope planning then becomes not “How do we divide the entire project into smaller pieces?” but rather “Which parts of the project scope can be logically merged into a work package?”
While this bottom-up method certainly provides more options than a two-dimensional WBS, it's worth questioning whether more flexibility automatically leads to more effectiveness. To determine this, we must first define what makes scope planning effective—something that is surprisingly rarely measured in project controls, despite its importance.
When is scope planning effective?
The main reason for defining work packages is to help the project manager maintain control of the overall project. This is easier to achieve when the number of active work packages is limited at any given time.
Introducing Planned Active Scope (PAS)
To help quantify this, we propose a simple measure: Planned Active Scope (PAS). PAS is defined as the average percentage of work packages that are active throughout the project lifecycle according to the baseline plan.
In project 1, on average 26% of the work packages are open throughout the project life cycle, while for project 2, PAS = 61%. The work packages defined in project 1 will clearly result in a higher degree of control and in less coordination work for the project manager.
Tracking Reality with Current Active Scope (CAS)
Of course, we know that a baseline plan rarely matches reality exactly. To track how well scope planning holds up during execution, we also introduce Current Active Scope (CAS), which looks at the percentage of open work packages over time based on the progressed current planning. A large variance between PAS and CAS may indicate a loss of control.
Conclusion
Dividing project scope into work packages is arguably the most important planning task of a project manager. The traditional Work Breakdown Structure can be useful, but its rigid approach may limit effective scope planning. A bottom-up approach with flexible work packaging allows project managers to better adapt to unique project needs. Metrics like Planned Active Scope (PAS) and Current Active Scope (CAS) can help quantify and enhance scope planning effectiveness.
