Work Breakdown Structure 
- A hierarchical list of work activities needed to complete the project; a description of the work to be performed broken down to its key components, down to the lowest level.
- Divide and conquer level
- Work breakdown structure identifies activities at a level useful for selecting the team with the proper skills.
- Based on staff number and estimates for the work breakdown structure, schedule cost and duration can be estimated.
Work Breakdown Structure Architecture 
- The work breakdown structure must cover all activities
- it is crucial to capture all disciplines or stages (requirements, design, implementation, testing…)
- Project manager must ensure everything is covered
Work Breakdown Structure Ganularity 
- Avoid too much detail and granularity.
- Don’t plan in more detail than you can manage
- Project manager has to train and trust the engineering team for those.
- Stop at a level where there is sufficient information for the people who will work on the activity.
- Obviously, don’t be too general either!
- A milestone is a significant event
- Usually associated with an interim deliverable
- For IIP, there can be a milestone at the end of each iteration.
- For eXtreme Programming (XP), there is typically a milestone every 1 to 3 weeks.
- Important to get the numbers right:
- Too few: big-bang effect, progress will be hard to track
- Too many: slows down project
- It is achieved as the result of the completion of a number of activities.
Work Packages 
- Lowest identifiable activities to be completed
- Description of work
- Staffing requirement (who, how many)
- Name(s) of personnel responsible for completion
- Budget ($, hours, …)
- Acceptance criteria (quality)
- Used mostly for large groups, or smaller groups of people who haven’t worked with each other before; rarely used in smaller organizations.
Activities and Tasks 
- Activity: the smallest component of the work breakdown structure, usually contains many tasks.
- Task: the lowest level of effort, typically achievable by one individual.
- Initially, an educared guess from past experience can be sufficient for the size of an activity. As requirements evolve, this size is estimated better.
- We cannot have all the details needed for a project plan at the beginning!
- It might be necessary later to break down larger activities
- IEEE 1074 provides a set of 65 activities carried out by software project activities (not all of which are needed for all projects, but still a good guidelines)
3 Level Work Breakdown Structure 
One possible way to tackle the work breakdown structure:
- Level 1: workflows
- Management, environment, requirements, design, …
- Level 2: phases
- Inception, elaboration, construction, transition
- Level 3: activities
- Lowest level that may be a work package or lead to a number of work packages
Creating the Work Breakdown Structure 
- Go through existing documents
- design documents
- customer conversations
- Synchronize the work breakdown structure with the process framework: keep in mind the life cycle when doing the work breakdown structure.
- Project manager: sanity check the work breakdown structure:
- everything is covered
- granularity is appropriate
 Prof. Shervin Shirmohammadi, University of Ottawa SEG4100 Course Notes, Lecture 4