Business Analysis
A business analyst can have two roles:
In a new development  or enhancement the role is to fully investigate requirements and all the implications for the new solution.
For an existing operation a business analyst will review the issues and requests for change to change systems or processes to improve the operation.
Business analysis can involve many techniques to assist in defining requirements. Popular techniques are:

Porters Five Forces
Power and Influence Grids
Fishbone diagrams
Data flow diagrams
Rich Pictures

Rayners Lane Consultants can assit with requirement analysis and consultancy.