Business Process Models: A completed transform often achieves a business milestone and a new state for some operational business thing(s). Example: claimant notified.
Fact Models: In fact models (structured business vocabularies) such states are represented by fact types, for example, claimant is notified (or claimant has been notified if you prefer). A fact model literally represents what things the business can know (remember) about completed transforms and other operational business events.
Business Rules: Business rules indicate which states are allowed or required. They should not reference business processes or business tasks by name, just the states they try to achieve. For example, a business rule might be: A claimant may be notified that a claim has been denied only if the specific reason(s) for denial have been determined.
This post excerpted from our new book (Oct, 2011) Building Business Solutions: Business Analysis with Business Rules. See: http://www.brsolutions.com/b_building_business_solutions.php