Conceptual integrity is an attribute of a quality design. It implies that a limited number of design "forms" are used and that they are used uniformly. Design forms include the way components inform their callers of error conditions, how the software informs users of error conditions, how data structures are organized, mechanisms for component communication, documentation standards, and so on.
When a design is complete, it should look as if one person created it all, even though it is the product of many devoted people. During the design process, there are often temptations to diverge from accepted forms. It is okay to give in to such temptations if the justification is for additional integrity, elegance, simplicity, or performance of the system. It is not okay to give in solely to ensure the designer x has left his mark on the design. Ego satisfaction is not as important as conceptual integrity.
