Quality Assurance in Scrum Applied to Safety Critical Software

Various agile methods have several quality assurance mechanisms embedded in the process itself, without any explicit QA role. In principle, the team takes care of quality assurance during sprints and as part of daily stand-ups, sprint reviews and retrospectives. We have defined SafeScrum, a variant of Scrum with some additional XP techniques that can be used to develop safety-critical software and have the software certified according to the IEC 61508 standard. This imposes a load of additional requirements on the process. In a recent industrial case, we have experienced that the quality assurance mechanisms in Scrum becomes insufficient. We have therefore analyzed the standard, consulted an independent assessor and worked with the Scrum team to identify necessary additional tasks for a team-internal QA role to be added to the SafeScrum process.