What Goes Into a Work Breakdown Structure?
A work breakdown structure separates data, services, a product, or all three, depending on the type and scope of a project. A WBS can be oriented around deliverables or around project phases and milestones for a process-centered approach. The process of subdividing a project into smaller components is called decomposition, and it can be completed by an entire project team as a group effort to ensure a comprehensive WBS. Doing so will give all team members a broad understanding of the project, thus improving communication, efficiency, and accountability.
Once the deliverables or milestones have been identified, the team can list the sequence of activities needed to complete each deliverable, thus decomposing the project into workable steps. The hierarchy of steps breaks the project into levels: The lowest level is the work package, which includes the activity or tasks required to produce a deliverable or complete a milestone. The pre-formatted structure of a template can help streamline the decomposition process and ensure that all necessary details are included.
The number of levels required for a WBS will depend on the characteristics of a project, but the levels must be sufficient to meet a project manager’s needs for accurate estimating and effective project monitoring. In a similar vein, the level of detail will vary, but one option is to follow the 8/80 rule, which says that the lowest level of work should require between eight and 80 hours. Based on this rule, if a work package takes more than 80 hours, it needs to be decomposed further.
A work breakdown structure can be formatted in various ways, including as an outline (basically, a numbered list), a hierarchical table, or a tree diagram. Regardless of format, a WBS will typically include outline numbering to represent the sequential order of each level and activity. To complement the WBS, a related dictionary may be created to provide detailed information about each element of the project, including definitions of each work package, effort level and duration of tasks, resources, and more. A WBS dictionary is generally presented in a table or spreadsheet format and serves as a detailed reference and planning tool.