Assessing the Understandability of UML Statechart Diagrams with Composite States - A Family of Empirical Studies

José A. Cruz-Lemus, Marcela Genero, Sandro Morasca and Mario Piattini

ABSTRACT    We have carried out a family of empirical studies to investigate whether the use of composite states improves the understandability of UML statechart diagrams. Our hypothesis derived from conventional wisdom, which says that hierarchical modeling mechanisms are helpful to master a system’s complexity. We carried out three studies. The first and the second ones were also replicated. The three studies differed in the size of the UML statechart models, the type of subjects (students vs. professionals), the familiarity of the subjects with the domains of the diagrams, and other factors. Surprisingly, our results do not seem to show that the use of composite states improves the understandability of UML statechart diagrams, like we expected.     The following picture describes the chronology and main features of the different studies.                       In the following table, you can find the experimental materials and the data collected in all the studies. First Study Second Study Third Study E1 R1 E2 R2 E3 C-DATA MAT C-DATA MAT C-DATA MAT C-DATA MAT C-DATA     MAT - Materials,  C-DATA - Collected Data Villahermosa R., Alarcos Research Group - E.S.I, University of Castilla-La Mancha, Spain -