Work Breakdown Structures

Mapping Out the Work Within a Project

Work Breakdown Structures - Mapping Out the Work Within a Project

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Break down your project into smaller, more manageable chunks.

You know what your project has to deliver and you're clear about what its scope is. So now you need to do some planning. But where do you begin?

Whether your project is big or small, one of the first challenges of project planning is to break the overall deliverable down into manageable chunks. Later, you'll use this to work out the schedule, identify the resources you'll need, and work out what the cost of it all is likely to be.

One of the most popular ways of doing this is to use a "Work Breakdown Structure." This technique is often used by professional project managers, using formal project planning methodologies. But you'll also find it useful for smaller, less formal projects – and even if your job title isn't "Project Manager." These might include a running marketing campaign, managing an office move or even organizing a company "away day."

A Work Breakdown Structure is a detailed list of all of the things that need to be delivered and the activities that need to be carried out to complete the project. As shown in figure 1 below, it's represented as a tree-structure, with each deliverable or activity broken down into further components.

Figure 1: Work Breakdown Structure Format

Work Breakdown Structure Diagram


There are several different approaches you can use when constructing a Work Breakdown Structures:

  • Process or activity-oriented – this involves breaking the project into the different activities it involves such as management, needs analysis, purchasing, testing, installation and training.
  • Achievement-oriented – this involves breaking down the overall project objective into achievements such as having fully trained users, and acceptance of a system against test plans.
  • Function or product-oriented – this involves breaking the project up according to the different parts of the final product e.g. hardware, software, data and service elements.

Different approaches suit different circumstances. The achievement-oriented approach is useful because it helps you to keep sight of how what you're doing contributes to the overall project deliverable. A function-oriented approach is useful where different people have different skills, and you need to organize work to take advantage of these different skill-sets. And a process-oriented approach allows you to break work down into conceptually simpler elements which can be approached one-by-one. Other approaches suit other situations, and some mix the approaches.

How to Use the Tool

Use the following steps to analyze your project:

  1. Choose which approach you want to use for your Work Breakdown Structure: process/activity; achievement; function/product-oriented; a different approach; or a combination of approaches.
  2. Break the project down according to this approach. And then break it down further so that the lowest level shows clearly-defined, achievable chunks of work. Try to create no more than 3 or 4 levels in total, with ideally no more than nine elements at each level. The final level of detail you go to will depend on the nature of the activities and the experience of the staff you will be assigning the activities too, but try to avoid going into too much detail while still ensuring that the Work Breakdown Structure is comprehensive. Your Work Breakdown Structure should certainly not be a list of one-hour jobs!

    Tip 1: How far to break down...

    What you're trying to do here is break the project down into manageable elements so that you allocate resource and estimate time and cost. Within your Work Breakdown Structure, try to break work down to a level where you understand tasks reasonably well, and can estimate resources needed with a reasonable level of confidence. (If you're doing this as part of a large program, break work down as far as individual projects that you feel comfortable delegating.)

    Tip 2: Beware exhaustion

    As you're breaking work down, it's easy to lose concentration, meaning that you can miss important tasks, and skip over unknowns without noticing them. Make sure that you validate your breakdown with key stakeholders to make sure it's comprehensive.

    If you're using this tool with people who want to get on with other stuff, it's easy to rush this stage and tolerate chunks of activity that are too large or are too loosely defined. Be careful and be thorough, particularly if you're likely to be facing deadlines or working within tight budgets.

    Tip 3: Be careful of commitment

    Use of Work Breakdown Structures is very much a "top-down" approach to identifying work. The thing most likely to cause you problems when using it are the "unknowns." These are tasks that you don't fully understand, and which could be quite simple, but could also be complex, expensive and time-consuming.

    If there are significant unknowns, mark them as such, and make sure you schedule early work to investigate them and clear them up. And make sure that you communicate these unknowns as risks to the clients of your project.

  3. If your project is reasonably large or complex, number each element or activity using a hierarchical numbering system as shown in figure 2 below. This allows everyone to be completely clear about which activity or milestone is being referred to in project reports.

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Figure 2: Part of an Example Work Breakdown Structure

Example Work Breakdown Structure


Tip 4:

If you are working with a team on this exercise, you may find it simplest to work with sticky notes on a large sheet of paper, and only transfer your WBS to a computer later.

Key Points

Good planning is a requirement for any successful project. And creating a Work Breakdown Structure during the planning phase is a good way of identifying the tasks that need to be completed.

Creating a Work Breakdown Structure is just one part of the wider activity of planning. More detail about planning can be found in Mind Tools Project Planning section and in our Bite-Sized Training session on Planning Small Projects.