The description of complex engineering problems as defined by ECSA is that the problem requires in-depth fundamental and specialised engineering knowledge; and have one or more of the characteristics:

• A systematic, theory-based formulation of engineering fundamentals required in the engineering discipline.
• Engineering specialist knowledge that provides theoretical frameworks and bodies of knowledge for the accepted practice areas in the engineering discipline; much of which is at the forefront of the discipline.
• Knowledge, including efficient resource use, environmental impacts, whole-life cost, re-use of resources, net zero carbon, and similar concepts, that supports engineering design and operations in a practice area.
• Knowledge of engineering practice (technology) in the practice areas in the engineering discipline.
• Engagement with selected knowledge in the current research literature of the discipline, awareness of the power of critical thinking and creative approaches to evaluate emerging issues.