Existing functionality as requirements?
I'm wondering what other's think about a dilemma we are having amongst BA's in my organization. When documenting requirements for maintenance to our Legacy system, some BA's feel it is quite acceptable to include current functionality as a requirement if they feel that the enhancement requirements may cause that current functionality to be affected or removed.
An example would be something like "Retain current functionality that allows users to update termination date."
I don't necessarily agree with this, though at times it may be valid to express to the development team that the enhancement requirements should not affect current functionality.
Anyone have any comments how to communicate things like this?
MPS
Existing functionality should be documented somewhere
I think in most cases it is appropriate to document existing functionality. Once you are maintaining a system, there needs to be a difference between "system documentation" and "project documentation." The system documentation represents the complete body of system capabilities and the project documentation represents the new requirements for a specific project.
Of course, there are some gray areas. As your colleague is doing, there are aspects of the system you expect to be impacted in some way. As part of project documentation, you might capture these as design or test considerations or project risks. In my initial agile experiences, I felt that the conditions of acceptance that accompany a product backlog item gave us a great tool to express these considerations at a granular level.
Another consideration is how deep a change you are making. Are you tearing apart a feature but keeping some aspects of it? The I think you definitely need to document the as is as part of the to be requirements. If you are making a tweak or minor enhancement, this activity might be much less valuable.
My 2 cents.
Laura, http://www.bridging-the-gap.com