Unified Modeling Language (UML) is the standard visual modeling language for Object Oriented (OO) systems development, but it has been criticized for its complexity, inconsistent semantics, and ambiguous constructs. A set of complexity indices for UML and the nine diagramming techniques in UML was compiled recently. The complexity analysis is formulated based on the number of constructs, associations, roles, and so forth, in a modeling method. We argue that this set of metrics provides an indication of the theoretical complexity of the modeling methods. On the other hand, the theoretical complexity of the modeling methods does not necessarily relate to the practical complexity. We hypothesize that UML’s complexity is not as daunting as the metrics imply, because not all the constructs are used all the time. Thus, in addition to theoretical complexity, a set of metrics for estimating practical complexity can be developed, based on the most commonly used constructs (instead of all constructs). In this research, we use secondary data to test our hypothesis that practical complexity is different from theoretical complexity.
