Systems-of-Systems: Engineering or Construct?
The concept of Systems-of-Systems (SoS) has become increasingly important across domains such as engineering, defence, healthcare, and digital infrastructure, describing complex assemblies of independent systems that collectively deliver capabilities beyond individual components. However, the concept remains debated: are SoS objective engineering entities or “constructs” used to interpret socio-technical complexity? Having its origins in the context of systems engineering and defence acquisition, SoS are defined by its operational and managerial independence, evolutionary development, and emergent behaviour. While these traits distinguish SoS from supersystems, they also reflect how complexity is framed. Two main perspectives are examined. The engineering perspective treats SoS as designable and controllable entities, emphasizing architecture, standards, governance, and lifecycle management approaches. Here, the challenge is extending traditional engineering methods to address scale, decentralization, and emergence. In contrast, the constructivist perspective sees SoS as interpretive frameworks for understanding loosely coupled, evolving systems shaped by organizational and social contexts. In this view, system boundaries, purposes, and identities are fluid and negotiated. Each perspective has implications. Engineering approaches support structure and measurable performance but may overlook human and political dynamics. Constructivist approaches highlight power, incentives, and adaptation but offer less practical design guidance. The paper argues that real-world SoS embody both views, combining engineered structures with emergent, socially shaped dynamics. It proposes a synthesized perspective that understands SoS as socio-technical phenomena—partly designed and partly constructed. This dual view suggests that effective SoS design and management require integrating engineering practices with insights from organizational theory, complexity science, and systems thinking.