Capturing Requirements

Capturing Requirements

1. System Failures

   • Over-Budget
   • Delivered Late
   • Do not do what users really want
   • Inadequate customer requirements
     • Fault of customer and consultant
     • Do not identify real needs of customer
     • Inconsistent and incomplete
     • Expensive to alter one development starts
       • Misunderstanding left unresolved

2. Adequate customer requirements

   • A description of what the system must provide
   • Properties the system must have
   • any constraints placed on system
     • WHAT it does, not HOW

3. Other considerations

   • required system may be an enhancement to an existing system
   • It may have to interact with other systems
   • Customer may not be end user
   • May be constraints on system's hardware

4. Writing Requirements

   • Natural language
   • Domain specific notation

5. Functional and non functional

   • Functional
     • Describe what system should do
   • Non-Functional
     • Specify performance or capacity
   • Not always clear

6. Size matters

   • Not an issue for SME IT Consultancy
   • Determining requirements grow with size of required system

7. Requirement gathering process

   • Can the system be built? is it feasible?
   • Who are the stakeholders?
   • What is the systems operating environment