An Evaluation of Design Rule Spaces as Risk Containers

It is well understood that software development can be a risky enterprise and industrial projects often overrun budget and schedule. Effective risk management is, therefore, vital for a successful project outcome. Design Rule Spaces (DRSpaces) have been used by other researchers to understand why implemented software is error-prone [1, 2]. This industrial case study evaluates whether such spaces are durable, meaningful, and isolating risk containers. DRSpaces were created from UML class diagrams of architectural design artefacts. In our study, object orientated metrics were calculated from the UML diagrams, and compared to the error-proneness of the DRSpace implementation, to determine whether architectural coupling translated into implementation difficulties. A correlation between architectural coupling and error-proneness of DRSpaces was observed in the case study. Software developers were asked to identify DRSpaces they found difficult to implement, in order to understand which factors, other than architectural coupling, were also important. The qualitative results show agreement between the code areas developers found difficult to implement and the error-prone DRSpaces. However, the results also show that architectural coupling is just one risk factor of many. The case study suggests that architectural DRSpaces can be used to facilitate a targeted risk review prior to implementation and manage risk.