Human activity system

A human activity system is a notional purposive system which expresses some purposeful human activity, activity which could in principle be found in the real world. Such systems are notional in the sense that they are not descriptions of actual real-world activity (which is an exceptionally complex phenomenon) but are intellectual constructs; they are ideal types for use in a debate about possible changes, which might be introduced into a real-world problem situation (Checkland, 1993: 314).