Breakdown structure for project management

How detailed should your WBS be?

There’s no general rule, but there are a two questions you can ask yourself to see whether you’ve gone down the rabbit hole deep enough:

  • Do you feel confident enough to create a detailed project plan with clear action steps? If the answer is no, you need to break up the WBS further.
  • What’s the estimated effort of the lowest level elements? Suppose you have a deliverable called electrical wiring at the lowest level. This includes ALL electrical wiring work in the vessel. In total, let’s say 150 person days of work. That’s huge and almost a project of its own! In this case it’s better to break work further down. For example: electrical wiring ground level, 1st level, 2nd level, sky deck etc. This way you get work packages that you can assign to someone in your team.

Remember: A WBS is supposed to help you. I know you are a perfectionist and you want to get the WBS right. Don’t fall into the perfectionist trap though. A WBS is supposed to help you and not cause you a headache. Spend as much time on it as you need to get a good feel for your project. And then move on to plan your project.

Why use a work breakdown structure?

There’s no doubt about it: Estimating projects can be confusing and somewhat difficult. But creating a project estimate doesn’t have to cause you heartburn. Asking questions, analyzing needs, and breaking your scope down into chunks can help.

Creating a work breakdown structure for any plan or set of tasks helps you get granular about the work that needs to be done on any given project. If you estimate your projects based on units—whether it’s weeks, days, or hours—using a work breakdown structure will help you understand very quickly if your estimate will exceed the intended budget or deadline.

Work Breakdown Structure Best Practices

As you’re working on your WBS it is helpful to maintain some best practices. Here are some things to keep in mind.

  • Use Nouns: WBS is about deliverables and the tasks that will lead to your final deliverable. Therefore, you’re dealing more on the what than the how. Verbs are great for action, and should be used in your descriptions, but for clarity, stick to nouns for each of the steps in your WBS.
  • Be Thorough: For a WBS to do its job, there must be no holes. Everything is important if it’s part of the course that leads to your final deliverable. To manage that schedule, you need a complete listing of every task, big and small, that takes you there.
  • Keep Tasks Mutually Exclusive: This simply means that there’s no reason to break out individual tasks for work that is already part of another task. If the work is covered in a task because it goes together with that task, then you don’t need to make it a separate task.
  • Go Just Deep Enough: You can get crazy with subtasks on your WBS. The WBS has to be detailed, but not so deep that it becomes confusing. Ideally, think maybe three or five at most levels.

Зачем декомпозировать

Понять, что и в каком поряд­ке делать. «Доба­вить счёт­чик на стра­ни­цу» кажет­ся зада­чей для фронтенд-разработчика. Но на самом деле он смо­жет сде­лать свою часть, толь­ко когда будет гото­ва база дан­ных и АПИ — меха­низм, по кото­ро­му эти дан­ные под­тя­ги­ва­ют­ся на сайт.

Если фрон­тенд попро­бу­ет сам пред­по­ло­жить, как будет выгля­деть запрос, то после инте­гра­ции могут всплыть непред­ви­ден­ные баги: бэкенд мог реа­ли­зо­вать АПИ не так, как думал фронтенд-разработчик. Деком­по­зи­ция помо­жет понять, с какой сто­ро­ны под­сту­пить­ся и в какой после­до­ва­тель­но­сти дви­гать­ся.

Оце­нить сро­ки. Когда зада­ча раз­ло­же­на на части, мож­но оце­нить по вре­ме­ни каж­дую и понять, сколь­ко потре­бу­ет­ся на всё вме­сте. Понят­но, что не полу­чит­ся запу­стить счёт­чик за день, если толь­ко на базу дан­ных и АПИ нуж­но два.

Упро­стить тести­ро­ва­ние. Тести­ро­вать про­ще, когда понят­но, что нуж­но про­ве­рить. В слу­чае со счёт­чи­ком: базу дан­ных, метод и вёрст­ку.

Рас­ста­вить при­о­ри­те­ты. Деком­по­зи­ция может пока­зать, что зада­ча боль­шая и тре­бу­ет вре­ме­ни. Напри­мер, если мар­ке­то­лог хочет ука­зать не толь­ко коли­че­ство поку­пок, но и коли­че­ство горо­дов, в кото­рые товар достав­ля­ли. Раз­ра­бот­чик может пока­зать, что делать всё вме­сте — две неде­ли, но счёт­чик поку­пок мож­но выка­тить быст­рее. А мар­ке­то­лог уже решит, как луч­ше посту­пить.

Work Breakdown Structure Diagram

The Work Breakdown Structure (WBS) is developed to establish a common understanding of project scope. It is a hierarchical description of the work that must be done to complete the deliverables of a project. Each descending level in the WBS represents an increasingly detailed description of the project deliverables.

The first two levels of the WBS (the root node and Level 2) define a set of planned outcomes that collectively and exclusively represent 100% of the project scope. At each subsequent level, the children of a parent node collectively and exclusively represent 100% of the scope of their parent node. Here is a Work Breakdown Structure example:

Tips for making a work breakdown structure

As you make a work breakdown structure, use the following rules for best results:

  • The 100% rule. The work represented by your WBS must include 100% of the work necessary to complete the overarching goal without including any extraneous or unrelated work. Also,  child tasks on any level must account for all of the work necessary to complete the parent task.
  • Mutually exclusive. Do not include a sub-task twice or account for any amount of work twice. Doing so would violate the 100% rule and will result in miscalculations as you try to determine the resources necessary to complete a project.
  • Outcomes, not actions. Remember to focus on deliverables and outcomes rather than actions. For example, if you were building a bike, a deliverable might be “the braking system” while actions would include “calibrate the brake pads.”
  • The 8/80 rule. There are several ways to decide when a work package is small enough without being too small. This rule is one of the most common suggestions—a work package should take no less than eight hours of effort, but no more than 80. Other rules suggest no more than ten days (which is the same as 80 hours if you work full time) or no more than a standard reporting period. In other words, if you report on your work every month, a work package should take no more than a month to complete. When in doubt, apply the “if it makes sense” rule and use your best judgment.
  • Three levels. Generally speaking, a WBS should include about three levels of detail. Some branches of the WBS will be more subdivided than others, but if most branches have about three levels, the scope of your project and the level of detail in your WBS are about right.
  • Make assignments. Every work package should be assigned to a specific team or individual. If you have made your WBS well, there will be no work overlap so responsibilities will be clear.

What tool should you use for creating a WBS?

Creating a WBS yourself can be challenging if your project is complex and has lots of deliverables. Pick a tool which can handle hierarchical diagrams well, otherwise you’ll be pulling out your hair soon. For this article I have evaluated the following tools:

  • MS Visio
  • MS Project
  • XMind
  • Excel and Powerpoint

All five candidates cost money but Excel and Powerpoint are probably already installed on your PC.

MS Visio: If you have the budget, I suggest getting Microsoft Visio. It’s the best solution for creating work breakdown structures (and professionally looking charts in general). It also comes with ready to use WBS templates, so you can get started quickly. You can get Visio for around $15 a month.

XMind: My second favorite is XMind. It’s actually a mind mapping tool, but you can also create top-down style WBSes easily. The current cost is around $5 per month.

MS Project: MS Project has support for WBS built in. It’s also a complex tool to use and the license is quite expensive. I would only recommend using MS Project if you are managing multi million dollar projects.

Excel: If you don’t want to pay for software, use MS Excel. Further down you’ll find an brief tutorial for creating WBS in Excel. You’ll also find a ready-to-use WBS template for Excel.

Powerpoint: Can you use Powerpoint as well? Sure. The drawing process is the same as in Excel. I just prefer Excel because I’m so used to it, but you can use either tool. Just make sure you chose a large page size to fit the entire WBS on the sheet.

Резюме файла WBS

Расширение файла WBS включает в себя один основных типов файлов и его можно открыть с помощью WebBlender 2 (разработчик — Tech4Learning). В общей сложности с этим форматом связано всего один программное (-ых) обеспечение (-я). Чаще всего они имеют тип формата WebBlender Project File. Большинство файлов WBS относится к Web Files.

Просматривать файлы WBS можно с помощью операционных систем Windows, Mac и Linux. Они обычно находятся на настольных компьютерах (и ряде мобильных устройств) и позволяют просматривать и иногда редактировать эти файлы. Рейтинг популярности файлов WBS составляет «Низкий», что означает, что данные файлы встречаются редко.

Work breakdown structure example

As you are thinking about how to make a work breakdown structure, let’s look at an example. This is a work breakdown structure for building a house.

Notice how the rules of building a WBS are applied in this example. First, the house building project is subdivided into three large sections that seem to make sense: foundation, exterior, interior. Those sections are further subdivided to one or two more levels for a maximum of three levels. The effort needed to build a house has been allocated across all of the work packages for a total of 100% effort. There is no duplication of work represented in this diagram. To further enhance this diagram, it would be possible to add the budget for each work package and assign a team.

Project Planning: The 100% Rule for a Work Breakdown Structure

➔Free 30-day WBS Software Trial

The Work Breakdown Structure (WBS) is both a model and a work measurement baseline tool for project management. The 100% Rule is an essential part of work breakdown structure methodology, in that application of this rule and its related concepts is critical in assuring the usefulness and accuracy of its application.

Work breakdown structure methodology is commonly used in construction and research and development (R&D) projects for planning and executing work, but can be useful in any field. Applying the 100% Rule, the top level of a work breakdown structure is the totality of the project, and lower levels categorize greater detail in a top-down structure under the first level.

The work breakdown structure shown below describes the work involved in a house construction project.

Figure 1. Work Breakdown Structure of a House

The top level of the diagram is the complete overview of all that needs to be accomplished. The structure then «breaks down» the work into major components. Where necessary, these components are then broken down further. Using the 100% Rule, the top level contains everything; however, the 100% Rule also applies at every level below that.

As an example, work breakdown structure element 1.2 includes all the planned work and budgeted money (cost estimates) for plumbing and element 1.2.2 below it includes all the efforts and dollars planned for plumbing fixtures and trim.

Accurate definition of tasks is a key to good management of a project, and the 100% Rule is an essential part of that. When a work breakdown structure is developed for a new project, it must represent and ultimately capture all efforts devoted to that project and, just as importantly, none that are not devoted to the project.

Figure 2. Work Breakdown Structure Level 2

Applying the 100% Rule to a Work Breakdown Structure

Applying the 100% Rule allows the manager to know that all efforts in each area are captured where they belong and also that nothing unrelated is included in an element.

The work breakdown structure contains a planning framework of planned outcomes that precedes project scheduling. Scheduling actually cannot be accomplished until a work breakdown structure is laid out. Being outcome oriented, the work breakdown structure defines everything that needs to be accomplished under the 100% Rule, regardless of work methodology and schedule changes. While methods and activity schedules might change during the project, the work breakdown structure should remain unaltered.

Application of the 100% Rule enables all outcomes to be defined before schedule planning begins. The work breakdown structure is the initiator in the planning process, as planned outcomes must be defined before methods and schedules can be considered. If outcomes are insufficiently defined, the project cannot succeed. Awareness of the 100% Rule enables and communicates full understanding of all necessary outcomes.

Once the project is underway the 100% Rule assists in assuring that project costs are properly shown in the accounting system. This is true for all projects, whether they are accomplished for another division in a company or for a regular paying customer. Application of the 100% Rule enables accurate costing, which is essential to budgeting similar efforts in the future.

The construction company building the house will record the costs actually experienced in the building project, and will use that experience in the next job to be started. The 100% Rule assures that all costs are accurately recorded. The experienced cost will be compared to what was expected, at all levels of the work breakdown structure. Planning efforts can then be improved to more accurately predict the next project’s schedule and cost, even if a different size and design of house is to be built.

The 100% Rule is especially important in cases like the home building example. A project planned and accomplished for a customer or for another organization must be carefully monitored so that the customer is charged only for legitimately relevant costs, and that the customer is aware of and confident in this.

Clear thinking in planning a project, which includes application of the 100% Rule in WBS preparation, produces accurate plans and accurate recording of cost estimates.


Dividing complex projects to simpler and manageable tasks is the process identified as Work Breakdown Structure (WBS).

Usually, the project managers use this method for simplifying the project execution. In WBS, much larger tasks are broken down to manageable chunks of work. These chunks can be easily supervised and estimated.

WBS is not restricted to a specific field when it comes to application. This methodology can be used for any type of project management.

Following are a few reasons for creating a WBS in a project:

  • Accurate and readable project organization.

  • Accurate assignment of responsibilities to the project team.

  • Indicates the project milestones and control points.

  • Helps to estimate the cost, time and risk.

  • Illustrate the project scope, so the stakeholders can have a better understanding of the same.

What’s the difference between a WBS and a project schedule?

Very simple. As I wrote before, the main reason for creating a work breakdown structure is to understand what tasks and deliverables a project has to take care of. We are not doing any planning here. It’s really just to understand the structure of a project — like you would try to understand the structure of a machine.

A project plan on the other hand is created to allocate project work on the timeline. It helps you see when a certain activity will be carried out. The schedule is also continuously update as the project progresses whereas the WBS is more static. You create it once, pin it to your wall and that’s it.

So, how are the WBS and the project schedule connected?

The WBS elements are mapped onto the project plan. But not in their original form. An item like ‘radar’ on the WBS would appear on our schedule as an action item, like Install radar system. Of course the schedule would be very detailed, containing activities around the design, development and testing of our radar: Design radar system, Implement radar system, Radar system test and so on. You get the point.

Enough of the theory! Let me show you how you create an actual WBS.

The Various Views of a Breakdown Structure

Tree Structure View

The tree structure view is the visualization of a breakdown structure. Among the various views, it’s most popular and easy-to-understand.

The outline view presents an easy to view and understand layout for the breakdown structure.

Hierarchical Structure

The hierarchical structure presents breakdown structure elements in a tabular form. It is similar to the outline view but with information presented in a table (without indentation). This view is extremely useful when your breakdown structure has many nested levels, which would make an outline view hard to presents elements’ neatly.

Level WBS Code Element Name
1 1 E-Octopus
2 1.1 Planning
3 1.1.1 Conduct Planning Kickoff Meeting
3 1.1.2 Develop Work Breakdown Structure

Potential risks of a Work Breakdown Structure

A Work Breakdown Structure of a project can also be used to identify potential risks within a project. A sub-activity that is not properly defined, can provide a definition risk. These risks need to be revised as the project progresses. By integrating the WBS in the organisational structure, it is easier for the project manager to plan moments where such risks can be identified.

Also when a project is behind schedule, it is possible to look at the WBS to see which sub-activities are the cause of this delay and quick adjustment can be implemented.

By working with colour codes, the status of each (sub)sub-tasks will be clear to everyone right away. This is comparable to the so-called Kanban system. For example, the colour red is for ‘late delivery’, blue for ‘delivered on time’, yellow for ‘sub-task at risk’ and green for ‘properly completed’. These colours are an effective way to map the progress of a project and draw attention to possible problem areas of the WBS.

Structuur van de uitsplitsing van het werk op basis van leveringen

Een Leverbaar werkonderbrekingsstructuur laat duidelijk de relatie zien tussen de project deliverables (d.w.z. producten, diensten of resultaten) en de scope (d.w.z. uit te voeren werk). Figuur 1 is een voorbeeld van een Deliverable Based WBS voor het bouwen van een huis. Figuur 2 is een voorbeeld van een op fase gebaseerde WBS voor hetzelfde project.

Figuur 1 — Structuur van de uitsplitsing van het werk op basis van prestaties

In Figuur 1 zijn de Elementen van Niveau 1 samenvattende leverbare beschrijvingen. De Niveau 2 Elementen in elke poot van de WBS zijn alle unieke deliverables die nodig zijn om de respectievelijke Niveau 1 deliverable te creëren.

Other Use Cases of Breakdown Structure

Resource Breakdown Structure

Resource Breakdown Structure (RBS) is a project management tool that provides a hierarchical decomposition of resources, either structured by resource category, types or by IT/business function that has resource needs.

Here is a Resource Breakdown Structure example:

Here are some examples of resource types.

  • Customer Support — The kind of customer and the type of support required for the project
  • Facilities: The facilities required for project (e.g. conference room, data center)
  • Equipment: Describe the hardware needed for the project (e.g. printer, scanner).
  • Software Tools: Describe the software requirements for the project (e.g. Visual Paradigm).

Risk Breakdown Structure

Risks are everything in any IT project. The existence of risk causes negative impact on project schedule, costs and quality. In project management, Project Manager is responsible for managing risks and to ensure that the project will be delivered on time, within project and up to the standard user expected. One of the popular risk management tool is the Risk Breakdown Structure.

Risk breakdown Structure is the hierarchical decomposition of risks, starting from the root node element that represents the project, and going down to the various risk categories, and then finer level risks.

Besides presenting project risks in a Risk Breakdown Structure, it is possible to combine the use of Color Legend in representing the impact of risk. Take a look at the Risk Breakdown Structure example below, a legend of Impact with five items has been setup, representing the five levels of impacts that risks may have on the project with five distinct color code.

Here is a Risk Breakdown Structure example:

There are many Risk Management Tool you can use in structuring risks. Besides Risk Breakdown Structure, you may consider using the Cause and Effect Diagram as well (also known as Fishbone Diagram).

Organizational Breakdown Structure

Organizational Breakdown Structure, or sometimes known as Organization Chart, is a widely used project management tool for representing project organization. It typically begins with the project sponsor, and with all key stakeholders included. In presenting the organization structure, consider the organization or group that is requesting the project and the level of their sponsorship and authority.

Here is an Organizational Breakdown Structure example:

Elements of a Work Breakdown Structure

A typical work breakdown structure is made up of several key components. They are as follows:

  • Task Number & Description: Giving each task a number makes it easy to identify them. A description will help define what the task is, which will provide direction for the team when it’s time to execute it.
  • Task Owner: The owner is the person, organization or department who oversees the task from assignment to completion and ensures that it has been properly executed.
  • Task Dependency: Some of the tasks on the path to the final deliverable will have to wait until another task is done or started before they can begin. This is called a “task dependency” and requires linking the two dependent tasks together in order to avoid slippage later in the project.
  • Cost of Task: Every task is going to have a cost associated with it. You’ll want to note that to keep track of your budget.
  • Start, Finish and Estimated Completion of Task: Add the start and finish dates for each task, and estimate the time you have on your schedule to execute it.
  • Task Status: The status of the task will show whether it’s assigned or not, in progress, late or complete, which helps with tracking.

What is a work breakdown structure?

The name is rather self-explanatory. A work breakdown structure starts with a large project or objective and breaks it down into smaller, more manageable pieces that you can reasonably evaluate and assign to teams. Rather than focusing on individual actions that must be taken to accomplish a project, a WBS generally focuses on deliverables or concrete, measurable milestones. These deliverables may also be called work packages, tasks, sub-tasks, or terminal elements. A work breakdown structure looks something like this:

Work Breakdown Structure Example (Click on image to modify online)

Creating a work breakdown structure in Excel

Creating a WBS in Excel is pretty straightforward. You draw a bunch of rectangles and connect them using connector lines. Here are the shapes you have to use:

By using connector lines, you can move the boxes around and the connections will remain intact.

Here’s how a WBS in Excel looks like:

Work Breakdown Structure (WBS) template for Excel

The downside of using Excel is that it takes more time to draw the WBS. Why? Excel won’t automatically re-arrange your structure when inserting new elements. Therefore you constantly have to rearrange existing nodes to avoid any overlaps. Also, the chart doesn’t look as clean as in Visio because Excel doesn’t automatically enforce identical node sizes.

How to Make a Work Breakdown Structure

A good Work Breakdown Structure is created using an iterative process by following these steps and meeting these guidelines:

  1. Gather Critical Documents
    1. Gather critical project documents.
    2. Identify content containing project deliverables, such as the Project Charter, Scope Statement and Project Management Plan (PMP) subsidiary plans.
  2. Identify Key Team Members
    1. Identify the appropriate project team members.
    2. Analyze the documents and identify the deliverables.
  3. Define Level 1 Elements
    1. Define the Level 1 Elements. Level 1 Elements are summary deliverable descriptions that must capture 100% of the project scope.
    2. Verify 100% of scope is captured. This requirement is commonly referred to as the 100% Rule.
  4. Decompose (Breakdown) Elements
    1. Begin the process of breaking the Level 1 deliverables into unique lower Level deliverables. This “breaking down” technique is called Decomposition.
    2. Continue breaking down the work until the work covered in each Element is managed by a single individual or organization. Ensure that all Elements are mutually exclusive.
    3. Ask the question, would any additional decomposition make the project more manageable? If the answer is “no”, the WBS is done.
  5. Create WBS Dictionary
    1. Define the content of the WBS Dictionary. The WBS Dictionary is a narrative description of the work covered in each Element in the WBS. The lowest Level Elements in the WBS are called Work Packages.
    2. Create the WBS Dictionary descriptions at the Level with detail enough to ensure that 100% of the project scope is covered. The descriptions should include information such as, boundaries, milestones, risks, owner, costs, etc.
  6. Create Gantt Chart Schedule
    1. Decompose the Work Packages to activities as appropriate.
    2. Export or enter the Work Breakdown Structure into a Gantt chart for further scheduling and project tracking.

Caution: It is possible to break the work down too much. How much is too much? Since cost and schedule data collection, analysis and reporting are connected to the WBS, a very detailed WBS could require a significant amount of unnecessary effort to manage.

There are many WBS software tools available. Some of them are based on mind mapping and others are drawing tools. You can read about these tools in this WBS software review.

Here is an example of how to make a WBS with MindView:

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