Confidence assessment framework for safety arguments

Abstract

Confidence in safety critical systems is often justified by safety arguments. The excessive complexity of systems nowadays introduces more uncertainties for the arguments reviewing. This paper proposes a framework to support the argumentation assessment based on experts’ decision and confidence in the decision for the lowest level claims of the arguments. Expert opinion is extracted and converted in a quantitative model based on Dempster-Shafer theory. Several types of argument and associated formulas are proposed. A preliminary validation of this framework is realized through a survey for safety experts.