Conceptual Schema Qualities
Correctness: the schema correctly (syntactically and semantically)represents the initial requirements;
Completeness: the schema represents all requirements;
Minimality: the schema represents only the requirements and every aspect of them appears only once in it;
Readability: the schema is easy to interpret and convey the requirements in a natural way;
Modifiability: the schema may be easily modified if requirements are changed;
Self-documentability: the schema does not need the addition of extra, external material.