Define Activities breaks the WBS work packages into the individual activities that must be performed to produce them. It produces the activity list, activity attributes, and the milestone list — the building blocks the rest of schedule planning sequences, estimates, and assembles.
On projects using rolling wave planning, near-term work is decomposed in detail while later work stays at a higher level until it is closer. Defining activities (the work) separately from deliverables (the WBS) keeps the schedule actionable.
Common pitfalls. Confusing activities with deliverables; missing activities that later appear as surprise work; and decomposing far-future work in detail that will only change.
Inputs, Tools & Techniques, and Outputs
Inputs
- Project management plan
- Enterprise environmental factors
- Organizational process assets
Tools & Techniques
- Expert judgment
- Decomposition
- Rolling wave planning
- Meetings
Outputs
- Activity list
- Activity attributes
- Milestone list
- Change requests
- Project management plan updates
How This Process Connects
Every process hands artifacts to other processes. Follow the flow of this one:
Where its inputs come from
- Develop Project Management Planproduces: Project management plan
Where its outputs go
- Perform Integrated Change Controluses: Change requests
More in Project Schedule Management
In the Domains & Principles View
The PMBOK® Guide frames this work through performance domains and principles:
In the Eighth Edition
In the Eighth Edition, Define Activities is merged with Sequence Activities, Estimate Activity Durations, and Develop Schedule into one process, Develop Schedule, in the Schedule performance domain. The single biggest consolidation in the edition: 4 processes to 1. Schedule drops from 6 processes to 3.