Agile Change Impact Analysis of Safety Critical Software

Change Impact Analysis (CIA) is an important task for all who develops and maintains safety critical software. Many of the safety standards that are used in the development and use of systems with a certified safety integrity level (SIL) requires changes of such systems to be initiated by a CIA. The resulting CIA report will identify planned changes that may threaten the existing safety level. The challenge with CIA is that there are no practical guidelines on how to conduct and report such an analysis. This has led to a practice where most changes lead to extensive up-front analysis that may be costly and delay the change process itself. In this paper we propose a new strategy for CIA based on the principles of agile software development and the SafeScrum approach to establish a more efficient in-process impact analysis. We discuss several benefits of this approach, like resource savings, shorter time to initiate the change process, better prioritization and management of the change process, and others.