A Controlled Experiment for Validating Class Diagram Structural Complexity Metrics

Measuring quality is the key to developing high-quality software, and it is widely recognised that quality assurance of software products must be assessed focusing on early artifacts, such as class diagrams. After having thoroughly reviewed existing OO measures applicable to class diagrams at a high-level design stage, a set of metrics for the structural complexity of class diagrams obtained using Unified Modeling Language (UML) was defined. This paper describes a controlled experiment carried out in order to corroborate whether the metrics are closely related to UML class diagram modifiability. Based on data collected in the experiment, a prediction model for class diagram modifiability using a method for induction of fuzzy rules was built. The results of this experiment indicate that the metrics related to aggregation and generalization relationships are the determinant of class diagram modifiability. These findings are in the line with the conclusions drawn from two other similar controlled experiments.