Existing Systems
Analyzing existing systems for requirements

One or more systems may exist that satisfies several of the business requirements. It is important to analyze these systems to determine what requirements have not been satisfied and why.

Also, these old systems may act as an initial prototype. The real life use of these systems will help prompt the users with additional ideas and therefore requirements.

It may be that the current system is on older technology or is running in an unsupported environment and needs to be rewritten. This is an ideal situation since it may mean that the application was providing most, if not all, of the requirements.

There should always be additional requirements which go beyond what the current system is providing. Even if none have been stated, an effort should be made to increase the functionality of the system since it is being redesigned and rewritten. Any investment made for the system at the time of the rewrite will be much less than if new requirements were identified and added later on.

This could also be the opportune time to rid the solution of any unwanted functionality. Simply do not capture and document the requirements. Alternatively, you may want to capture them and mark them as out of scope or as no longer required, “a retired requirement”.

When gathering requirements, never settle for the following statement:

This requirement is not clear and will never be able to be traced. Go thru the application and capture all the detailed requirements of the current system.

ClearlyPUT's Requirementing uses existing systems as a source for business requirements.

Summary

Gather requirements from the old systems. Understand why these requirements were satisfied. Take this opportunity to include additional functionality. Provide detailed requirements for the current systems.

Requirementing Steps