Component-Based Software Engineering

Domain Components

Domain components for an insurance company may include Bill, Policy, and Claim components. It is unlikely they will find broad reuse outside of that domain.

BUSINESS CASE 
Domain build cost = sum of costs for the domain components and supporting
                   components + application framework costs
Improvement in productivity factor for domain components = 10
Your application reuse savings = ((10 x domain build cost) x (number of applications - 1))
                                  - Complexity cost
Your cost per user = (domain build cost + complexity cost)/sum of users across all applications
                      (ignoring overlap in users)