Towards the definition and use of a core set of archetypal structures in system dynamics

Abstract

There has been considerable research in the field of system dynamics over the last decade concerned with defining generic structures and templates by which to classify structures and behavioural insights in dynamic systems. These have appeared both in stock/flow and causal loop terms. This article focuses on generic causal loop structures more commonly known as system archetypes, a profusion of which have now been defined. The purpose of the article is to improve the usefulness of system archetypes both as free standing devices to aid model conceptualisation and as a means of disseminating insights arising from models. In order to achieve this three postulates are made: First, that system archetypes can be usefully condensed down to a more understandable core set of four totally generic archetypes, consisting of the four ways of ordering a pair of reinforcing and balancing feedback loops. These are described, named and current archetypes mapped onto them with specific examples. Second, that for every "problem" archetype there exists a closed loop "solution" archetype. It is suggested that some misunderstandings with current archetypes arise from the fact that they often combine problem and solution links in the same diagram. Third, that each archetype has important characteristics, which are vital to understanding the role of archetypes in assisting systematic thinking. The particular characteristic introduced and highlighted is the concept of organisational boundaries. The article concludes by discussing the importance of the reduced set of archetypes, and organisational boundaries in particular, in explaining some barriers to implementing systematic thinking, using a range of examples encountered by the author in recent consulting practice. © 2003 John Wiley and Sons, Ltd.