Evaluating structural validity of class diagrams by measuring the number of highly responsible classes

Design models are often developed using UML class diagrams. Based on past questionnaire surveys reported by Lange and Nugroho, we assumed that the existence of highly responsible classes indicate that a class diagram was created through the proper consideration of the structure of the system. Thus, we analyzed the structure of UML design class diagrams. Specifically, we measured our novel metrics (the amount of highly responsible classes in class diagrams), and investigate the correlations between our metrics and the structural validity of design. In this study, we propose two viewpoints to distinguish large values which indicate high responsibility. Additionally, we conducted the evaluation experiment using 65 design class diagrams, which were originally submitted to a Robot Contest on the domain of embedded systems and evaluated by software development experts based on structural validity. Then the correlations between our novel metrics and the experts' qualitative assessment were analyzed.