How Regulations of Safety-Critical Software Affect Technical Debt

In recent years in the software industry, the use of safety-critical software is increasing at a rapid rate. However, little is known about the relationship between safety-critical regulations and the management of technical debt. The research is based on interviews with 19 practitioners working in different safety-critical domains implementing software according to different safety regulation standards. The results are three-fold. First, the result shows that performing technical debt refactoring tasks in safety-critical software requires several additional activities and costs, compared to non-safety-critical software. This study has also identified several negative effects due to the impact of these regulatory requirements. Second, the results show that the safety-critical regulations strengthen the implementation of both source code and architecture and thereby initially limit the introduction of technical debt. However, at the same time, the regulations also force the software companies to perform later suboptimal work-around solutions that are counterproductive in achieving a high-quality software since the regulations constrain the possibility of performing optimal TD refactoring activities. Third, the result shows that technical debt refactoring decisions are heavily weighed on the costs associated with the application's recertification process and that these decisions seldom include the benefits of the refactoring activities in a structured way.