5.1 What is the Problem Domain?

The problem domain is the domain in which a system is going to be used. Therefore, it is important to look at requirements from an operational point of view. A system or any other product enables somebody or some equipment to do something. It is this enabling aspect that is at the heart of requirements engineering in the problem domain. Faced with the challenge of eliciting requirements from potential users one might therefore be tempted to ask a user the question:

What do you want the system to do?

Some users will have little or no idea of what they want the system to do. Those who have an existing system will usually have ideas about how to improve the system, but when there is no existing system this source of inspiration is not available. Answers may be forthcoming from those with insight into what is possible, but they are most likely to come up with a solution because the question is focusing on the functionality to be provided by the intended system.

To avoid this premature jump into the solution domain, it is necessary to ask the question:

What is the purpose of the system you want?

When considering the purpose of a system, people immediately think about what they want to be able to do with the system, rather than how...