A requirements review is a manual process that involves people from both client and contractor organisations. They check the requirements document for anomalies and omissions. The review process may be managed in the same way as program inspections (see Chapter 24). Alternatively, it may be organised as a broader activity with different people checking different parts of the document.
Requirements reviews can be informal or formal. Informal reviews simply involve contractors discussing requirements with as many system stakeholders as possible. It is surprising how often communication between system developers and stakeholders ends after elicitation and there is no confirmation that the documented requirements are what the stakeholders really said they wanted. Many problems can be detected simply by talking about the system to stakeholders before making a commitment to a formal review.
In a formal requirements review, the development team should ‘walk’ the client through the system requirements explaining the implications of each requirement. The review team should check each requirement for consistency and should check the requirements as a whole for completeness. Reviewers may also check for:
- Verifiability Is the requirement as stated realistically testable?
- Comprehensibility Do the procurers or end-users of the system properly understand the requirement?
- Traceability Is the origin of the requirement clearly stated? You may have to go back to the source of the requirement to assess the impact of a change. Traceability is important as it allows the impact of change on the rest of the system to be assessed.
- Adaptability Is the requirement adaptable? That is, can the requirement be changed without large-scale effects on other system requirements?
Conflicts, contradictions, errors and omissions in the requirements should be pointed out by reviewers and formally recorded in the review report. It is then up to the users, the system procurer and the system developer to negotiate a solution to these identified problems.
NASA checklist for requirements reviews