Defining Metrics for Conceptual Schema Evolution

It is generally believed that a well-designed Conceptual Schema will remain stable over time. However, current literature rarely addresses how such stability should be observed and measured in the operational business environment with evolving information needs and database structures. This paper sets up a framework for stability of conceptual schemas and proceeds to develop a set of metrics from it. The metrics are based on straightforward measurements of conceptual features. The validity of the set of metrics is argued here from theory, operational validity may be demonstrated by a longitudinal case study into the evolution of conceptual schemas. The main contribution of this paper is the realization that the measurement of conceptual schema stability is an essential step for understanding and improving current theories and best-practices for designing high-quality schemas that will stand the test of time.