In GreenDesk, the term Expert System is used in the traditional sense of a system that applies complex rules, conditions, and constraints to model data - and answers to questions - to guide users through completion of worksheets and forms and to alert users to issues - and especially to design choices - that may impact on your green scheme certification score or your application for certification for an industry standard.
All data that is entered into the Project Model Database is monitored by the Expert System, and throughout GreenDesk the system - indicates using special warning icons and diagnostic messages - exactly where any problems or "bad apples" may exist in the model and design.
This mini-tutorial is essential reading for all new GreenDesk users: The UNDEF symbol: "Please feed me, I'm undefined (null)"