T he Unified Modeling

Language (UML) emerged in the mid-1990s through the combination of previ-ously competing object-oriented (OO) software engineering methods developed by Booch [1], Jacobson et al. [6], Rumbaugh et al. [8], and others. Control over its formal evolution was placed in the hands of the Object Management Group (www.omg.org), and the language has become widely accepted as a modeling stan-dard for OO software development. A large number of practitioner articles and books, and some contributions by academic researchers, have been devoted to articulat-ing various aspects of the language, includ-ing guidelines for using it [5]. UML per se is a language, not a methodology, so it is not surprising these guidelines are not always consistent [4]. Despite widespread interest in UML, there is little quantitative evidence on the level and nature of UML use. Our study examines seven UML components used in systems analysis and design and addresses three key questions. First, to what extent are these UML analysis components being used and for what pur-poses? Second, do differences in the levels of component use and the reasons for these dif-ferences reflect the apparent complexity of the language [7, 9]? Third, how successful is UML in facilitating communication within software development teams? The research began with a review of the UML literature and some preliminary inter-views with UML practitioners and their clients. Following this, we developed a Web survey targeted at analysts familiar with OO techniques and UML in particular. UML 1.5 contains nine basic diagrams [3]—six of thes