Peter Checkland (1930- ) is emeritus professor of systems at Lancaster University and a noted systems thinker. Checkland’s Soft Systems Methodology (SSM) evolved as a response to the models developed by earlier systems thinkers such as von Bertalanffy and Beer. These theorists had used biological systems and engineering/cybernetics as a way of trying to model human-activity systems. Checkland recognised that such human activity systems are too ‘messy’ to be modelled in this simple fashion:

a key feature of messes and difficult policy issues is that there are valid different perspectives on the issue or situation, which interpret information quite differently.

Chapman 2002

Checkland’s own experience as a consultant to the British Aircraft Corporation’s Concorde project showed the problem with what he termed ‘hard systems’ approaches: thinking like a systems engineer at the time (What is the system? What are its objectives?) he failed ‘to think of it as anything other than an engineering project’. The project was running late and was over-budget and thus failing against its originally stated objectives.

However, there was a larger, political set of objectives at work which were more concerned with demonstrating British sincerity towards Anglo-French joint ventures than delivering the first supersonic passenger airliner. This was at a time when the UK was applying for membership of the European Community in the face of the then French President De Gaulle’s veto (Ramage and Shipp 2009 p150). This experience led Checkland to realise that there would always be a number of models and worldviews (he used the German term Weltanschauungen) in play when studying a system which described the multiple views of reality as perceived by the various participants within that system.

In fact, a better version of systems thinking needed to be developed which could incorporate the greater degrees of complexity Checkland recognised in larger, human activity systems. He started from the presumption that ‘systems are in the eyes of the beholder’ and decided to construct a model that could recognise and work with the ambiguities inherent in a situation. A way of demonstrating this distinction between Checkland and his predecessors can be shown by looking at the degrees of complexity shown respectively by an insect’s digestive system, or a computer’s operating system, or that of the workings of HM prisons service. The prisons service is something far less well-defined and commonly understood than the workings of the insect, and views of the prisons service will differ greatly dependent on the experience that person has had of the system (whether a prisoner, judge, policeman, prison guard, etc.).

A prison can variously be conceived of as:

a punishment system, a rehabilitation system, a system to deter, a system to protect society and as a “university of crime”.

Jackson 2003 p187

As an example, Jackson explains that no prison:

is “a punishment system” or a “rehabilitation system” or “a system to protect society”; these are notional concepts relevant to exploring the realities of any actual prison.

Jackson 2003 p18

Checkland embraces this additional complexity and tries to build it into his model (see the diagram below).

Peter Checkland
Checkland’s original seven-step learning cycle of Soft Systems Methodology (SSM) (from Jackson 2003, Chapman 2002).  The first formulation of Checkland’s model is expressed in his work ‘Systems Thinking, Systems Practice’ (1981).

The original model incorporated 7 steps (as shown above). Once a problem has been identified (step 1), the participants in the process formulate their ideas in a series of ‘rich pictures’ (step 2). Rich pictures are ‘actual drawings that allow the various features of a problem situation, as it is perceived, to be set down pictorially for all to see.’ (Jackson 2003).

The thinking then transfers ‘above the line’ in the diagram, where relevant human activity systems are selected and from these, ‘root definitions’ are formulated (step 3). A root definition is intended to capture the purpose of the system and its intended core transformation. It should incorporate the factors brought to mind by the mnemonic ‘CATWOE’:

C – Customers – the beneficiaries of the system

A – Actors in the system, who carry out or cause to be carried out the main activities of the system

T – Transformation – the means by which defined inputs are transformed into defined outputs

W – Weltanshauung or worldview – an outlook, framework or image which makes this particular root definition meaningful

O – Ownership – some agency having a prime concern for the system and the ultimate power to cause the system to exist

E – Environmental constraints on the system, features of the system’s environments and/or wider systems which it has to take as ‘given’ (from Checkland 1981 p224-5)

The Weltanshauung is the most intriguing of these elements, and shows the level of complexity that Checkland’s model is designed to deal with. It recognises that each root definition could reflect a different way of conceiving the problem situation. Once these conceptions have been sufficiently developed, they are then brought back ‘below the line’ in the diagram to be compared with the real world situation. SSM therefore articulates a process whereby different Weltanshauungen are described and then discussed in relation to human activities. Step 6 then identifies an agenda for improvement, and step 7 is about making the changes.

SSM, Checkland believed, should not be cut off from the day to day activities of an organisation but integrated with them. The idea is that as many parties as possible are involved in the study of the system. However, this may cause problems in reconciling the various world views when one comes to redesign the system. Commentators such as Prof Mike Jackson have pointed out that Checkland’s SSM requires consensus, but does not specify how to achieve this, meaning that the powerful have the opportunity to disproportionately skew outcomes in their favour (Shipp and Ramage 2009 p153).


Chapman J 2004 ‘System Failure’ Demos: London

Checkland P 1981 ‘Systems Thinking Systems Practice’ Wiley and Sons: Chichester

Jackson, M 2003 ‘Systems Thinking: Creative Holism for Managers’ Wiley and Sons: Chichester

Ramage M and Shipp K 2009 ‘Systems Thinkers’ Open University: Milton Keynes