Safety case is an efficient method for helping the developing company to focus on the simple but important question "How do you know that your system is safe enough?" The idea of a Safety case is not to provide a mathematical or statistical proof, but to argue as one would in a court of law – thus the name Safety case.
Experience has shown that preparing and understanding a SC is difficult and time consuming.
SINTEF has experience both with ordinary safety cases and "Agile" safety cases.
The reason to include an Agile approach is to avoid too much documentation, to improve communication between the stakeholders and to get a faster approval of the system. This is important as the technology changes faster and faster. In addition, the software has to be updated more frequently, due to increased cyber-security threats.
All too often, suppliers have left the important task of creating a safety case to the end of the project. The reason for this has often been that "we need to have complete knowledge of the system before we write the Safety case". This has turned out to be a costly solution. It is much more efficient to build the Safety case by inserting information when it becomes available during project development – an agile approach also resulting in increased safety awareness and understanding.