V.: Effects of defects in UML models: an experimental investigation

The Unified Modeling Language (UML) is the de facto stan-dard for designing and architecting software systems. UML offers a large number of diagram types that can be used with varying degree of rigour. As a result UML models may con-tain consistency defects. Previous research has shown that industrial UML models that are used as basis for implemen-tation and maintenance contain large numbers of defects. This study investigates to what extent implementers detect defects and to what extent defects cause different interpreta-tions by different readers. We performed two controlled ex-periments with a large group of students (111) and a group of industrial practitioners (48). The experiment’s results show that defects often remain undetected and cause mis-interpretations. We present a classification of defect types based on a ranking of detection rate and risk for misinter-pretation. Additionally we observed effects of using domain knowledge to compensate defects. The results are generaliz-able to industrial UML users and can be used for improving quality assurance techniques for UML-based development