In the course of my studies, I remember encountering two approaches explicitly targeting the design of complex systems: * "Interaction design for complex probl

In the course of my studies, I remember encountering two approaches explicitly targeting the design of complex systems: * "Interaction design for complex problem solving: Developing useful and usable software" (a book by B. Mirel, 2004) * Cognitive Dimensions Framework (the best place to start is probably http://www.cl.cam.ac.uk/~afb21/publications/BlackwellGreen-CDsChapter.pdf http://www.cl.cam.ac.uk/~afb21/publications/BlackwellGreen-C... ) But as others have pointed out, it depends on what kind of complex system you are talking about.