Certification and Safety Cases

Certifying agencies have begun to require a safety case as part of the product certification process. The standards upon which such certification regimes are built define properties that the safety case must have, e.g., “compelling,” and “valid”, yet leave these terms undefined. Unaided judgment of these properties leaves doubt about how approval will proceed. We introduce an operational definition of these terms in the form of a comprehensive certification process for certification based upon the submission of a safety case. The process defines how certification could be conducted. The process also defines the properties that an acceptable safety case must have since successful certification with this process implies that the safety case has the desired properties. We illustrate our approach to certification using hypothetical argument fragments.