For some applications, the users can articulate processing rules that describe the software's behavior. In other cases, the job of an analyst or a designer transforms the user's desires into procedural descriptions of the software.
It's often easiest to provide concrete examples of expected results. Either the ultimate users or intermediary analysts may find it helpful to create a spreadsheet that shows sample inputs and expected results. Working from user-supplied, concrete sample data can simplify the software being developed.
Whenever possible, have real users produce concrete examples of correct results. Creating procedural descriptions or software specifications is remarkably difficult. Creating concrete examples and generalizing from the examples to a software specification is less fraught with complexity and confusion...
