This chapter recalls the issues surrounding decision-making in the so-called volatile, uncertain, complex, and ambiguous environment (identified by the acronym VUCA). It lists the requirements around decision-making graduate attributes for the accreditation of engineering programs, questions the limits of the weight of rules in relation to decision-making, and positions the study in the light of complex systems. The chapter then discusses the theoretical framework used. Its state of the art specifies the different approaches relating to the concept of reliability, in particular with a note on lines of research that approach reliability first from the angle of organizational failure and then from the angle of increased reliability (actionist movement, highly reliable organizations stream). In methodological terms, the chapter then presents the Design Based Research conducted since 2015 to infer and strengthen transversal decision-making skills in complex situations among engineering students.