PROJECT SCOPE MANAGEMENT
6.4 Scope definition and the work breakdown structure
Scope definition is the process of breaking work into manageable pieces. The work breakdown structure is the output of the process.
6.4.1
Work breakdown structure
A work breakdown structure (WBS) is a deliverable-oriented grouping of the work in- volved in a project that defines the total scope of the project. It serves the purpose of breaking down the whole project work into manageable pieces. The WBS is a foun- dation document in project management, as it provides the basis for planning and managing projectschedules,costs,resources, andchanges.
The WBSs can be organised byproject products,project phases, orproject manage- ment process group. The presentation of a WBS can be visualised by aorganisational chart form, atabular form, and aGantt chart.
Activity 6.3
Organisation of the Work Breakdown Structure
Read through the example WBS structures in Figures 5-6, 5-7, 5-8, 5- 9 and Table 5-3 in Schwalbe’s text. Try to answer the following questions: How is each example WBS organised? What is the visualisation form used by each example WBS? What are the advantages and disad- vantages of organising WBSs by project products, project phases, and project management process group? What are the advantages and dis- advantages of visualising WBSs by the organisational chart form, tabular form, and Gantt chart form?
The WBSs present project information in a hierarchical form. The lowest level of the WBS representswork packages, which are tasks at the lowest level of the WBS. As a rule of thumb, average work package should represent roughly80 hours of effort. For smaller projects with relatively short time frame, a work package might represent 40 hoursof work. For larger projects, this number might be100 hours.
It should be pointed out that there are two main advantages for creating WBSs by using the project management process groups of initiating, planning, executing, controlling, and closing aslevel 1in the WBS:
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Allow the project team to follow good project management practiceË
The WBS tasks can be mapped more easily against time.Finally, it is important to involve the entire project team and customer in creating and reviewing the WBS.
6.4.2
Approaches to developing work breakdown struc-
tures
Developing the WBS is an important task itself. The following approaches exist for developing WBSs:
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the analogy approachÌ
the top-down approachÍ
the bottom-up approachÎ
the mind-mapping approach. Using guidelinesSome organisations require prescribed form and content for WBSs for particular projects,
e.g., the U.S. Department of Defense. Many organisations provide guidelines and tem- plates for developing WBSs as well as examples of WBSs from past projects. The Project Management Institute (PMI) developed a WBS Practice Standard to provide guidance for developing and applying the WBS to project management.
The analogy approach
The analogy approach of developing WBSs is to use a similar project’s WBS as a starting point. Some organisations keep a repository of WBSs of past projects, so that a project manager can easily select a past WBS as the starting point of creating the project’s WBS.
The top-down and bottom-up approach
The top-down approach starts with the largest items of the project and breaks them into their subordinate items. It then refines the work into greater and greater levels of detail. The top-down approach is suitable for project managers who have vast technical insight and a big-picture perspective.
As a comparison, thebottom-up approachfirst identifies as many specific tasks related to the project as possible. It then aggregates the specific tasks and organises them into summary activities. The bottom-up approach can be verytime-consuming but a very
effectiveway to create a WBS.
Mind mapping
Mind mapping is a technique that uses branches radiating out from a core idea to structure thoughts and ideas. It is a more visual and less structured approach, allowing people to write and even draw pictures of ideas in a non-linear format. Mind mapping can be combined with the top-down and bottom-up approach to develop WBSs.
6.4.3
Advice for creating a WBS
The previous section discussed several approaches for developing WBSs. In fact, these approaches are often combined together. There are somegeneral principlesfor creating good WBSs: