Assessing the effect of requirements traceability for software maintenance

Advocates of requirements traceability regularly cite advantages like easier program comprehension and support for software maintenance (i.e., software change). However, despite its growing popularity, there exists no published evaluation about the usefulness of requirements traceability. It is important, if not crucial, to investigate whether the use of requirements traceability can significantly support development tasks to eventually justify its costs. We thus conducted a controlled experiment with 52 subjects performing real maintenance tasks on two third-party development projects: half of the tasks with and the other half without traceability. Our findings show that subjects with traceability performed on average 21% faster on a task and created on average 60% more correct solutions — suggesting that traceability not only saves downstream cost but can profoundly improve software maintenance quality. Furthermore, we aimed for an initial cost-benefit estimation and set the measured time reductions by using traceability in relation to the initial costs for setting-up traceability in the evaluated systems.