An empirical study of the nesting level of composite states within UML statechart diagrams

Abstract

As UML statechart diagrams are the core for modeling the dynamic aspects of software systems, we have been studying their understandability for the last three years. In previous researches, we have already studied the relationship between many of the constructs of the UML statechart diagrams and the effect that they have on the understandability of the diagrams themselves. We have also performed a family of experiments whose results indicated that the use of composite states make UML statechart diagrams easier to understand. This fact motivated us to go a step further and investigate if the Nesting Level of Composites States (NLCS) has an impact on the understanding of the diagrams through a controlled experiment and a replication. In this paper, we present the experimental process and the main findings of them. Unfortunately, the obtained results are not quite conclusive and we have not been able to find an optimal use of nesting within UML statechart diagrams and further empirical research is needed, considering more complex UML statechart diagrams. © Springer-Verlag Berlin Heidelberg 2005.