The word expectations has probably been abused and misunderstood more than any other word in the computing culture. To many project managers and systems analysts, expectations are simply those elements of the "requirements" that were not specified by the client. To others, expectations are the difference between what the client wants and what they really need. For the battle- hardened project manager, expectations are a wish list that begins a series of hard negotiations to reduce the expectations to minimum requirements. Finally, expectations are a hopelessly vague set of fuzzy requirements that defy documentation.
However, it is our experience that expectations are a related set of specific requirements that can be analyzed and modeled . It's just that data flow and data model and other system-oriented techniques do not capture all the requirements for a business system.
When business experts or clients talk about their expectations, they are talking about three related concepts:
As shown in Figure 23.1, these can be seen as subsets .
Figure 23.1. Expectations