Short note: change management

Change management (change control) is the configuration management process that makes sure every change to a software system is requested, analysed, approved, made and recorded in a controlled way. Its aim is to allow necessary changes while keeping the system stable and costs under control.

Change control process (Sommerville and Pressman):

1. Change request: a user or developer submits a change request form (CRF) describing the change.
2. Validation and analysis: the request is checked to see if it is valid and not a duplicate. Its impact, cost and risk are analysed.
3. Decision: a change control board (CCB) or change control authority approves or rejects it, considering cost, benefit and schedule.
4. Engineering change order: an approved change is assigned to a developer with a description of the work.
5. Implement: the developer checks out the affected items, makes the change, and the change is reviewed and tested.
6. Check in and baseline: the changed items are checked in, a new version is created, and the CRF is closed.

Change request --> Analyse impact/cost --> CCB
                                           |
                    +----------------------+
                    |                      |
                Rejected               Approved
             (inform user)                 |
                                 Check out, modify
                                           |
                                  Review and test
                                           |
                                 Check in, new version

Example: a customer asks for SMS alerts in a banking app. The CCB estimates 10 person-days, approves it for the next release, and the change is tracked until it is tested and released.

Benefits: prevents uncontrolled changes, keeps a history of who changed what and why, and helps estimate the effect of changes.