Work breakdown structure (WBS) in project management
Divide et impera. The divide and conquer strategy was applied by Julius Caesar to conquer the divided Gaul twenty-two centuries ago. Today, it is still used in various fields such as politics, sociology, algorithmics, and project management. Only project managers do not use divide et impera to conquer people, but their projects and the chaos that comes with it. A divide and conquer paradigm is used in a project management work breakdown structure (WBS).
This article will take a deep dive into a WBS in project management and how project managers can leverage it to become Julius Caesars for their projects.
What is WBS in project management?
Work breakdown structure (WBS) in project management visually outlines a complex and multi-stage project, starting from the most overarching objective down to the smallest chunk of deliverables. As Mike Clayton claims, WBS simply breaks the work down into a structure. A WBS is a type of a divide and conquer method because it allows project managers to handle their projects one or a few deliverables at a time, instead of completing a whole project in one go.
It usually comes with a glossary — a document that briefly describes each deliverable and a work package, which facilitates project team members to understand the scope of the tasks they must complete to deliver the work.
Types of WBS in project management
There are two types of WBS: deliverable-based and phase-based. These two differ in how they identify the project structure elements in the first level of the WBS.
- A deliverable-based WBS visualizes the relationship between the project deliverables (e.g., a product or service) and the scope of the work. It breaks down the project scope into control accounts and divides it into project work packages and tasks.
- A phase-based WBS typically breaks the first level down into five elements (initiation, planning, execution, control, closeout) and then identifies deliverables within those phases.
Work breakdown structure hierarchy
When it comes to the hierarchy, work breakdown structures usually consist of a minimum of three levels. To visualize and help you understand those levels better, we will create a WBS chart for a classic project plan. Let’s assume that the project we want to complete is a wedding coming up in a few months. Here’s what a WBS for such a project could look like.
What are the 4 WBS levels?
Since a WBS is a hierarchical structure, it usually consists of three to four levels. The number of levels of the work structure will depend on the size and complexity of a given project. But in the case of our sample project, four levels are enough.
WBS level 0
The first (top) level of the WBS is the project title and the final deliverable. According to our project, the title is a “Wedding Plan.” Therefore, a deliverable is a memorable day for two people saying “I do” for life. The zero level is the broadest and states the project’s entire scope.
WBS level 0.
WBS level 1
The second WBS level is control accounts. Control accounts is a management control point that groups work packages and measures their status. As such, it controls areas of the project scope. Control accounts include project major parts, phases, systems, or features the customer expects you to deliver. The main parts of the wedding project are all the components that regular weddings consist of, such as: choosing an attire, organizing meals, taking care of the guests, delivering speeches, etc.
WBS level 1.
WBS level 2
The third WBS level is work packages. Each work package in a WBS is a deliverable (a noun), not an action (a verb). In other words, a deliverable is not what your team will be doing but what the customer or other stakeholders is going to get when the package is completed (outcome). When the work packages come together, they constitute the control accounts level.
It is important to note that work packages must be small enough to allow you to manage, coordinate, execute and monitor them easily. After all, this is the main reason for creating a WBS in the first place. And while you are at the work packages level, you also can define the time each deliverable will require for completion (in hours) and their costs (to calculate the cost of the project).
WBS level 2 (in green). Note how every single element on the Wedding Plan WBS is a noun (deliverable).
Let’s come back to the example from above. The “Bride’s Attire” is a small task that one can easily manage, coordinate, execute, and monitor. When completed, the deliverable is that the bride will have separate attires for the individual wedding events (“Attire for Wedding Party” control accounts). Additionally, you could add how many hours it would take to purchase such attire and the overall cost.
WBS level 3
The last one of the WBS levels is activities. The completion of the set of activities leads to the delivery of the individual work package. For instance, sample activities for the work package “Bride’s Attire” consist of three tasks: Wedding Attire, Luncheon Attire, and the Departure Attire.
WBS level 3 (in pink).
Here, the tasks under level 3 “Music” are additionally further broken down into smaller sub-tasks (level 4). Each of the finished sub-tasks, activities, and packages should bring you closer to the victory (completed project).
How to create a work breakdown structure?
To use a work breakdown structure in project management effectively, it is important to arrange all the elements of a project in accordance with the 100% rule. For this purpose, you can use a variety of tools, including spreadsheets.
But if you really want to create a WBS that you will later on use to effectively manage your project, you may want to consider using dedicated software. The software we recommend is BigGantt — the most powerful Gantt chart application for Jira on the market. It comes with all the features you are going to need when creating and working with your work breakdown structure.
WBS software—essential features for project managers
The great thing about project management software is that it is designed to accommodate your work breakdown structure with some convenient features. Here’s what you should look for in your WBS software.
Task breakdown
WBS is about breaking down work packages into tasks and sub-tasks, and BigGantt supports you all along the way. It will let you allocate task owners and set priorities and durations for every task. And if you have already created a WBS for your project with Jira or Excel, you can import it to BigGantt.
Tasks breakdown. You can move individual tasks up and down with a drag-and-drop feature.
Project tracking
No project is the same. Your WBS may consist of hundreds of work packages and tasks with individual duration periods you want to monitor. Therefore, you need features that give you a quick overview of your project, down to the shortest task. BigGantt has several ways of tracking progress and time, including progress bars, milestones, and critical paths. It also supports resource planning and basic resource management.
Hint: If you need more advanced resources management options, you may consider using the Resource module which is part of the BigPicture app.
Bars and percentages (as well as percentage bars – not shown on the screen) indicate task progress.
Task dependencies
The bigger and more complex project, the more room for dependencies between tasks to emerge. After you finish creating your WBS, you will notice that some tasks cannot start or finish until another has started or finished. Such mutual dependencies can cause delays across your project—unless you can spot them early.
That is why marking task dependencies is another must-have feature that you will find in BigGantt. It will let you visualize dependencies between specific tasks and between the groups of deliverables or whole initiatives. Moreover, you will also get several types of dependency links and auto-scheduling functionality with so-called Strong links.
Strong links will auto-schedule the linked tasks for you.
Task scheduling
Scheduling is the process of positioning tasks on a timeline so that you know which phase a given task belongs to and when it should start and finish. However, scheduling each task by hand may not be practicable if your WBS is large. So how about some automation? The BigGantt app can auto-schedule tasks and generate a project schedule for you. This way, you can save time and keep hundreds of tasks under control and within deadlines.
Scenarios
What-if scenarios are a fantastic addition to a strategic planning toolset. They provide a possibility to test how certain variables could affect your plan, project, or timeline. So instead of hoping that the structure you have created will work, you can try different scenarios against such variables as delays, risks, resources availability, and workload allocation. Scenarios will help you make informed decisions and decrease uncertainties.
New Scenario modal window.
Integrations
So far, you and your team might have been using different management tools where they add and track their work. Luckily, switching to BigGantt does not mean you will need to give up on them. You can integrate BigGantt with other applications and import/export some data to keep your team in a loop.
Creating WBS—good practices and rules
To make your WBS work as intended, there are a few rules worth keeping in mind.
The 100% rule
One of the most critical work breakdown structure principles is the 100% (one-hundred percent) rule. It states that the sum of the work spent on the child elements (e.g., a set of tasks) must be 100% equal to the work effort assigned to the parent element (e.g., a work package). The 100% rule applies to all WBS levels, and the total percentage sum cannot be any higher or lower.
The 8/80 rule
The 8/80 rule will help you decide whether a given work package is small enough. The 8/80 means that a WBS work package should not take less than 8 (eight) hours of effort and a the same time, not more than 80 (eighty).
Work package assignments
You should assign each work package to a specific team or individual. If you create your WBS right, there will be no overlap in work and responsibilities.
Unique deliverables
You must not add to your WBS any work package, task, or other work more than once. Otherwise, you will violate the 100% rule and receive incorrect effort and cost calculation results.
Clear deadlines
If you set deadlines for the work items at every WBS level, you will be able to estimate the overall timeline for your project. It will help you keep your team on track, communicate with stakeholders, and ensure timely project delivery.
Outcomes over actions
When naming project deliverables, try to use nouns rather than verbs. It does not mean that you cannot use verbs at all. But according to the PMI's WBS definition, nouns are preferable.
How a WBS helps the project manager?
A WBS is a fantastic tool for breaking down large complex projects, visualizing their scope, and managing them in an organized manner. It will also help you be more accurate when:
- Establishing dependencies between the tasks.
- Assessing and mitigating potential risks.
- Estimating the costs of your project.
- Developing a project schedule.
- Determining a project timeline.
- Planning project resources.
- Assigning tasks and roles.
- Tracking the progress.
Work breakdown structure formats
The hierarchy of a work breakdown structure can take different formats. We have used a tree (or flowchart) format for the Wedding Plan. The tree hierarchy structure is similar to an organization chart and allows easy editing. Other WBS types you can use include:
Outline WBS
The WBS outline is the simplest format for breaking down a large project or deliverable. It resembles a table of contents in a book or a master thesis.
A partial representation of a Wedding Plan as an outline WBS.
Table WBS
A simple table is another way you can visualize the hierarchy of your project work structure. Similarly, you can use a spreadsheet to create your WBS to achieve this format.
A partial representation of a Wedding Plan as a table WBS.
Gantt chart WBS
You can visualize your WBS as a Gantt chart. A Gantt chart will include both your project work hierarchy and a timeline. This way, you will be able to link task dependencies, mark project milestones, and track when each activity is supposed to start and end.
A sample Gantt chart for the House Building project created with BigGantt.
Gantt charts complement WBS in project management pretty well. They help estimate the period of individual tasks and visualize the overall project timeline from the initiation to completion.
WBS in Agile project management
There is a common belief that WBS goes well only with traditional project management methodologies such as Waterfall. Classic methodologies, in contrast to Agile methodologies, suit very well projects whose goals are unlikely to change. Because of that, a work breakdown structure is thought not to be flexible enough to match the Agile iterative nature.
Classic/Waterfall (incremental) vs Agile (iterative) cycles of work.
But that is not entirely true. Just think about it—if a WBS represents all the work that your teams need to put into the project, then a product backlog typical to Agile projects is sort of a WBS, too. In Agile, you break down large epics or features into smaller units (user stories) as you are about to develop them and control them during the sprints. In Waterfall, you break down the entire project into smaller units (work packages and tasks) upfront and control them throughout the project.
So in this sense, a work breakdown structure is the equivalent of the product backlog. However, please keep in mind that in agile projects, the scope of work comes from the backlog and you do not know what you will be working on straight away. This is in contrast to the Waterfall methodology where you have defined the entire scope of the project before the project execution has begun.
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