Time-based decomposition is one of the methods for dividing and organizing larger tasks into smaller activities or sub-tasks. The key advantage of this method is to use time periods as the major parameter for identifying sub-tasks and defining their durations or time-frames. The method is widely used in IT and software projects which require strict breakdown of tasks by constituent parts or elements with succinct and measurable time limits.
In terms of time-based decomposition, a broad activity or task can be represented as a timeline with several or multiple small milestones that signify beginning or completion of an event. A larger task consists of smaller events which have certain time-frames and are separated from each other by milestones. A milestone has no time length; it is just a mark on a task timeline. All milestones of a single timeline separate events from each other and create an event grid.
The method of time-based decomposition can be performed as a process that consists of the following steps:
- Identify a broad task or activity to be decomposed
- Define key elements of the task (objectives, requirements, performance metrics, quality checks, others)
- Estimate time required to complete the task
- Develop a timeline that shows the required time length
- Identify what events cause the task to move towards its completion
- Define event milestones (special points in time to define start date and completion date for every event)
- Develop an event grid based on milestones
- Add the grid to your timeline
- Associate events with sub-tasks on the grid
- Set time-frames of events as durations of sub-tasks
- Use milestones to separate sub-tasks from each other
Develop a decomposition chart that includes sub-tasks and timeline.