Design patterns and fault-proneness a study of commercial C# software

In this paper, we document a study of design patterns in commercial, proprietary software and determine whether design pattern participants (i.e. the constituent classes of a pattern) had a greater propensity for faults than non-participants. We studied a commercial software system for a 24 month period and identified design pattern participants by inspecting the design documentation and source code; we also extracted fault data for the same period to determine whether those participant classes were more fault-prone than non-participant classes. Results showed that design pattern participant classes were marginally more fault-prone than non-participant classes, The Adaptor, Method and Singleton patterns were found to be the most fault-prone of thirteen patterns explored. However, the primary reason for this fault-proneness was the propensity of design classes to be changed more often than non-design pattern classes.