Deriving Key Features of a System-of-Systems Complexity Evaluation Framework from an Industrial Case Study Analysis

Assaying the importance of system complexity for the systems engineering community

“…Despite several decision support or evaluation tools being available to characterize projects and systems 16,43,44,56–58 , each of which may be useful for complexity evaluation, there is a challenge in coalescing several perspectives and measures into a coherent whole. One such decision support tool, developed and used by Thales Group, has been previously reviewed and helped to define the identified system complexity factors used here 58–60 . The Thales Group “Complexity Profiler” evaluates the complexity of a candidate system against eight complexity factors which are evaluated on an integer scale (1–4): the impact of the environment on the solution, the stability of the operational concept, user diversity, external stakeholder involvement, life cycle interlacing, systems engineering effort, the stability of system behavior, and the engineering organization.…”

“…We use the term “Technical Novelty” to represent the number of similar systems the organization has already developed in the same deployment domain, the amount of reuse in the system, the number of high added‐value elements, and the level of innovation required to deliver the system. This notion of system complexity has been given multiple different terms: “the difficulty of creation,” 10 the “implementation context and system context,” 43 “socio‐political complexity,” 2–4,23,32,61 and “system engineering effort and criticality.” 59 …”

“…A commonly used term is “Structural Complexity,” 2–4,22,24,32 which we define as the number, diversity, distribution, connectivity, and constraints on constituent components, subsystems, systems, and operational nodes. The term is also related to what has been termed the “implementation context,” 43 and the “system engineering effort and criticality,” 59 …”

“…We use the term “Behavioural Complexity” to mean the ability to define and predict system modes, functions, states, behavior, performance, and missions, including degree of autonomy and the impact of the environment. This is akin to what has been termed “dynamic complexity,” 3,4,20,21,23,32,64 relating to both the “strategic” and “system context,” 43 and has also been termed “operational concept stability” and “system behaviour stability.” 58–60 …”

“…“Development Complexity” is the amount, and availability, of resources required to develop the system throughout its life cycle, including the interlacing of programs, the degree of challenge of requirements, and the maturity of technology, regulations, standards, processes, and methodologies. Again, this notion of system complexity has been used under various labels: “the difficulty of creation,” 10 “socio‐political complexity,” 2–4,23,32,61 It relates to the “system context” and “implementation context,” 43 and has also been termed “development process complexity,” “operational complexity,” and the “impact of environment on the solution.” 59 …”