Concepts: Baselining
Topics
Definition 
A baseline is a 'snapshot' in time of the development artifacts in the Implementation Model. It provides an official standard on which subsequent work is to be based, and to which only authorized changes can be made. After an initial baseline is established every subsequent change to a baseline is recorded as a delta until the next baseline is set.
When baselines are created, all constituent components and baselines need to be labeled such that they are uniquely identifiable and re-createable.
Explanation
There are several advantages to creating baselines:
- A baseline provides a stable point, and a snapshot of the development artifacts.
- Baselines provide a stable point from which new projects can be created. The new project, as a separate branch, would be isolated from subsequent changes to the original project (on the main branch).
- Individual developers can take baselined components as a basis for updates in their isolated private workspaces.
- A baseline provides a way for a team to roll back changes in case the updates are considered to be unstable or suspect.
- A baseline provide a way to reproduce reported bugs given that you can recreate the configuration when a particular release was built.
Use
The best time to create a baseline is at the end of each phase (major milestone). However, during the course of the project baselines may be created at the ends of iterations (minor milestones). A good time to create a baseline may be after an iteration when certain critical level of development has be done, and different teams can use the baseline to branch off for individual development efforts. As such, baselining would occur more frequently than just at the end of iterations.
Names of the major milestones associated with the lifecycle phases are:
- Lifecycle Objectives Milestone (Inception Phase)
- Lifecycle Architecture Milestone (Elaboration Phase)
- Initial Operational Capability Milestone (Construction Phase)
- Product Release Milestone (Transition Phase)
