ISO/IEC/IEEE 15026-4:2021 pdf download – Systems and software engineering — Systems and software assurance — Part 4: Assurance in the life cycle.
While the assurance claim can be derived from a number of sources, it is normally motivated by potential real-world adverse consequences associated with the capability of the system, the intended use of the system, and the outcomes produced by the system. The body of information showing that the system-of-interest achieves the assurance claim is called assurance information, which includes: a) the assurance claim, b) the required degree of confidence in achievement of the assurance claim, c justification of selection of the assurance claim, d) evidence of achievement of the assurance claim, adequate for the required degree of confidence, and . e) an argument about how the evidence in d) supports achievement of the assurance claim a. The item b) includes the required integrity level of the system with respect to the assurance claim. Items c), d), e) should be adequate for the required degree of confidence in b). The item e) should reflect satisfaction of the assurance claim (item a]) commensurate with the required degree of confidence. NOTE Assurance case as specified by ISO/IEC 15026-2 can be used as a structured approach to compile these items of assurance information. The argument often includes several different kinds of sub-arguments, e.g. arguments based on design rationale, use of defensive design techniques, verification and validation results, performance of similar systems or products, conformance to standards, or field data. An argument consisting of different kinds of sub-arguments gains more confidence in achievement of the assurance claim. The assurance information is maintained and updated throughout the system life cycle, in accordance with the change of the system during maintenance and redevelopment. The assurance information is a configuration element of the system-of-interest and associated with all the system life cycle processes.