Benefits of traceability in software development

Abstract

For an engineer to be able to modify successfully a complex computer-based system, he will need to understand the system's functionality. Traceability can help the engineer to gain that understanding, but several surveys have observed that traceability information is poorly recorded. This thesis argues, based on a survey of nine aerospace projects, that one of the main causes of poor recording is that Traceability does not directly benefit the development process. The recording of traceability information is best performed by the engineers directly involved in the development process, yet it is precisely these engineers who seem to obtain no direct benefit in performing this task. This can be summarised as the Traceability Benefit Problem. To overcome this problem the recording of traceability data must provide immediate, tangible benefits to the engineers involved in the current development process. A related problem that occurs in large multi-team projects that follow development processes based on predictive models (such as Waterfall or VModel) is the changing of interface documentation without adequate negotiation (referred to as Throwing the Problem over the Wall). This thesis describes, in detail, how a small automotive sensor project addressed these problems by developing a Requirements Traceability system that enabled the reuse of software and provided a basis for the negotiation of changes with their customer. Analysis of the lessons learnt from the automotive sensor and aerospace projects lead to the definition of the Traceable Development Contract. The contribution of this thesis is the description and discussion of the Traceable Development Contract, a method of coordinating the interaction of related development teams in development process that is based on a predictive development model. The Traceable Development Contract is proposed as a means of controlling the upstream team bias with respect to the imposition of changes, by employing traceability to provide a basis for the negotiation of change. By VI employing traceability in this way, it becomes beneficial to the development engineers and therefore overcomes the Traceability Benefit Problem. Finally, the thesis considers how the Traceable Development Contract traceability information can be exploited further to provide solution maturity and design metrics.