Operational research OR is regarded by many as being in crisis. If OR is taken to be ‘classical OR’, this is indisputable … If, however, the definiti… - Mike Jackson

We consider the notion of "system" as an organising concept, before going on to look in detail at various systemic metaphors that may be used as a basis for structuring thinking about organisations and problem situations.

A.D. Hall's (1962) classic account of the methodology was based on his experience with the Bell Telephone Laboratories. Hall sees systems as existing in hierarchies. In systems engineering, plans to achieve a general objective must similarly be arranged in a hierarchy, with the systems engineer ensuring the internal consistency and integration of the plans, The methodology itself ensures the optimization of the system of concern with respect to its objectives. This requires a number of steps, the most important being problem definition, choosing objectives, systems synthesis, systems analysis, systems selection, system development, and current engineering. With Hall, the system of concern is usually a physical entity.

The classification of a system as complex or simple will depend upon the observer of the system and upon the purpose he has for considering the system.