A model, or representation of requirements is a record of data which a group of people agreed to call requirements.
The definition bundles several important ideas:
- The definition does not say what a requirement is. This is better done separately, since it is a hard problem itself.
- What qualifies as a requirements model is decided by a group of people. It is a convention. It may be a convention local only to a small group of people, or a wider one, such as an industry standard.
- The model or representation must be a record, something physical or digital, which can be moved around, so that it can be accessed by different people in the same way. So, if you are now thinking about something, and you are calling those things requirements, and I have no other way to access them except to ask you, then that is not a representation/model of requirements.
- A model can look in any way which is accepted by those who consider it a model in the first place: text, graphics, multimedia – this does not matter at all in the definition above.