Evidence management for compliance of critical systems with safety standards: A survey on the state of practice

Context
Demonstrating compliance of critical systems with safety standards involves providing convincing evidence that the requirements of a standard are adequately met. For large systems, practitioners need to be able to effectively collect, structure, and assess substantial quantities of evidence.

Objective
This paper aims to provide insights into how practitioners deal with safety evidence management for critical computer-based systems. The information currently available about how this activity is performed in the industry is very limited.

Method
We conducted a survey to determine practitioners’ perspectives and practices on safety evidence management. A total of 52 practitioners from 15 countries and 11 application domains responded to the survey. The respondents indicated the types of information used as safety evidence, how evidence is structured and assessed, how evidence evolution is addressed, and what challenges are faced in relation to provision of safety evidence.

Results
Our results indicate that (1) V&V artefacts, requirements specifications, and design specifications are the most frequently used safety evidence types, (2) evidence completeness checking and impact analysis are mostly performed manually at the moment, (3) text-based techniques are used more frequently than graphical notations for evidence structuring, (4) checklists and expert judgement are frequently used for evidence assessment, and (5) significant research effort has been spent on techniques that have seen little adoption in the industry. The main contributions of the survey are to provide an overall and up-to-date understanding of how the industry addresses safety evidence management, and to identify gaps in the state of the art.

Conclusion
We conclude that (1) V&V plays a major role in safety assurance, (2) the industry will clearly benefit from more tool support for collecting and manipulating safety evidence, and (3) future research on safety evidence management needs to place more emphasis on industrial applications.