Problems to be tackled in requirements elicitation [McDermid 89] include:

• problems of scope:
  • the boundary of the system is ill-defined
  • unnecessary design information given
• problems of understanding
  • users don't fully understand their needs
  • users don't understand computer capabilities and limitations
  • requirements engineer doesn't understand the problem domain
  • users and engineers speak different languages
  • 'obvious' information may be omitted
  • different users have conflicting views
  • requirements vague and untestable
• problems of volatility
  • requirements evolve over time

J. McDermid, 'Requirements Analysis: Problems and the STARTS Approach', in IEE Colloquium on Requirements Capture and Specification for Critical Systems, Digest no. 138, Nov. 1989.