30 things that go wrong in object modelling with UML 1.3

The authors offer a catalogue of problems experienced by developers, using various object modelling techniques brought into prominence by the widespread adoption of UML standard notations. The catalogue is revised to reflect changes made between UML versions 1.1 and 1.3, in which a number of semantic inconsistencies in the notation were fixed. Notwithstanding this, developers still seem to create inordinate problems for themselves by pursuing unproductive development strategies that are apparently fostered by UML. This article shows how the biggest problem by far is cognitive misdirection, or the apparent ease with which the rush to build UML models may distract the developer from important perspectives on a system. This problem is more serious than the outstanding inconsistencies and ambiguities which still exist in UML 1.3. A number ofinadequacies are also highlighted, where UML somehow still fails to express what we believe are important semantic issues. While UML itself is mostly neutral with respect to good or bad designs, the consequences of allowing UML to drive the development process include: inadequate object conceptualisation, poor control structures and poorly-coupled subsystems.