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SSM in more detail

Stage 1: Diagramming (Rich pictures)

Rich pictures are a compilation of drawings, pictures, symbols and text that represent a particular situation or issue from the viewpoint(s) of the person or people who drew them. They can show relationships, connections, influences, cause and effect. They can also show more subjective elements such as character and characteristics as well as points of view, prejudices, spirit and human nature. Rich pictures can both record and evoke insight into a situation. They can be regarded as pictorial 'summaries' of the physical, conceptual and emotional aspects of the situation at a given time. They are often used to depict complicated situations or issues. They are drawn both prior to analysing a situation, when it is unclear which parts of a situation are particularly important and as an inquiry proceeds as a means to monitor what, if anything has changed. They help show which parts should be regarded as structure and which as process.

Rich pictures can be invaluable in communicating issues between groups of people where there are cultural or language differences. Drawings, pictures and text can provide the basis for the shared understandings needed to enable further dialogue (and perhaps further rich pictures). A rich picture offers a great deal of scope for creative thinking and freedom in how you represent your ideas. A lack of drawing skill is no drawback as symbols, icons, photographs and/or text can be used to represent different elements.

Drawing a rich picture is often done most effectively as a communal activity, so that the different stakeholders in a situation can portray things as they see them. They are made up from:

  • pictorial symbols
  • key words
  • cartoons
  • sketches and symbols
  • title

It is usually best to avoid too much writing, whether as commentary or as ‘word bubbles’ coming from people’s mouths, although some people find it easier to use short phrases than to try to come up with a pictorial representation of some complex ideas.


  1. A rich picture is an attempt to assemble everything that might be relevant to a problem situation. You should try to represent every observation that occurs to you.
  2. Use words only where ideas fail you for a sketch that encapsulates your meaning.
  3. Do not seek to impose any particular style or structure on the picture. Place the elements on your sheet of paper wherever seems appropriate. At a later stage you may find that the placement itself was significant.
  4. If you ‘don’t know where to begin’, the following sequence may help to get you started:
    1. first look for the elements of structure in the situation (these are the parts of the situation that change relatively slowly over time and are relatively stable – the people, official organizations, elements of the landscape, perhaps)
    2. next look for elements of process within the situation (these are the things that are in a state of change – the activities that are going on)
    3. then look for the ways in which the structure and the processes interact.
  5. Avoid thinking in systems terms: that is, using ideas like ‘Well, the situation is made up of an ecosystem, an agricultural production system and a planning system.’
  6. Your picture should include not only the ‘hard’ factual data about the situation but also the ‘soft’ subjective information.
  7. Look at the social roles of those involved within the situation, and at the kinds of behaviour expected from people in those roles. If you see any conflicts, indicate them.
  8. Finally, include yourself in the picture, or, if you are doing it as a member of a group, include the members of the group. Make sure that your roles and relationships in the situation are clear. Remember that you are not an objective observer, but someone with your own set of values, beliefs and norms that colour your perceptions.

Stage 2a: Root definition and its formulation

Root definition (RD) is part of the terminology of soft systems methodology (SSM). A root definition is a statement that concisely describes a system of interest. It is usually a single sentence starting ‘A system to…’ and it should include mention of all the key elements of the system. It usually takes several iterations before a complete definition is agreed. Various mnemonics have been suggested to help the process of formulating a root definition and check that all the elements are present. One such is CATWOE which identifies the key elements as:

Customer: Who are the clients, beneficiaries, victims (of the system)?
Actors: Who conducts the activities in the system?
Transformation: What specified elements are changed by the system (i.e. how are inputs transformed into outputs)?
World view: What is the thinking that justifies the transformation?
Owners: Who can stop this activity or demolish the system?
Environment: What constraints will hinder the activities of the system?

The CATWOE procedure is used to check that all necessary elements are included in the root definition before proceeding to a conceptual modelling phase. Experienced SSM practitioners iterate between RD, CATWOE and conceptual modelling as part of a process of learning their way to something that feels right and which is likely to provide the most insight in the situation. There is no formulaic way of doing this.

Root definitions can be ‘activity-based’ (e.g. a system to deliver an operational information system to support purchasing decisions against environmental criteria) or ‘issue-based’ (e.g. a system to build stakeholding of a sceptical staff for an information system designed to aid environmental decision making). What is important to remember is that the root definition is not an attempt to describe some real, existing ‘system’ but an attempt to learn about a complex situation so as to make changes. For example, the Olympic Games could be seen as any of the following:

  • A system to bankrupt self-selecting cities on a four year cycle
  • A system to institutionalise a global celebration of sporting prowess and cooperation amongst nation states.
  • A system to provide inputs into a global capitalist system in which there are limited number of beneficiaries.
  • A system to allow sports ministers to extract money from treasuries for the development of a national sporting competence.

Which of these you (or many others) chose in a given situation would depend on your context and interests (hence ‘system of interest’) and what you felt would lead to the most creative insights and learning.

Other systems practitioners have built on CATWOE to develop other mnemonics that have been found useful. For example change statements can be developed from conversation mapping or rich pictures and then developed and modelled so that they can be used to probe a situation to enable decisions to be made about whether such action is feasible and what might be the ensuring benefits. Practitioners from the Systemic Development Institute (SDI 2005) use a TWOCAGES interpretation of each change statement. This involves the following:

Transformation: Assemble a clear statement that describes the current situation, the desired future state of the situation and the way the future state can be attained.
Worldview: Detail the values and ethical justification for proposing the T.
Owner: Identify who will control (own) the proposed T.
Client(s): List who will be the beneficiaries and victims of T.
Actors: Nominate those who will do the activities required to achieve the T.
Guardians: Proposed guardians for the community who will monitor the implementation of T and inform the owner of unintended consequences.
Environment: Identify influences outside the control of the owners that may help or hinder the T in the near and medium term.
System: List all the activities that must be initiated and coordinated to achieve T. Express this relationship in a conceptual systemic model.

The impact of the probe developed in TWOCAGES can then be applied to the current situation and a planning or project group, for example, assesses the significance of the change. The insights gained from this stage should then be conveyed to the community or other relevant stakeholders, for final ratification and to government departments for approval and resourcing where appropriate.

One of the drawbacks of CATWOE and TWOCAGES is in conflating what might be called the 'beneficiaries' of the system with 'victims' of the system, under 'C' (clients). In a workshop centred on developing operational research (OR) methods for environmental management held at Hull University, UK s(Midgley and Reynolds 2001) participant OR practitioners in the field of environmental management decided to modify the CATWOE mnemonic to BATWOVE. This stands for:

Beneficiaries: ‘immediate’ and ‘ultimate’ beneficiaries of the proposed transformation;
Actors: those who should make the transformation happen—the people involved in making the system work;
Transformation: the purpose of the system—what input is changed into what output?
World-view: the perspective (including values) from which the transformation looks meaningful and desirable;
Owners: those who have the power to stop the transformation happening (to stop the system from working);
Victims: those affected in a negative way (in their terms) by the transformation; and
Environmental constraints: those factors that have to be taken as given in designing a system.

Stage 2b: Conceptual modelling

Conceptual models were devised to represent a purposeful activity system through a set of logical actions implied by the description of the system, or root definition as it is known in SSM. This defensible logical structure for a conceptual model may be derived from a root definition even though knowledge of any 'real-world' version of the activity is lacking. In some ways a conceptual model is like an activity sequence diagram, but is clearly aimed at representing a conceptual system as defined by the logic of the root definition and not just a set of activities.

The elements of a conceptual model are:

  • large circle representing the purposeful activity;
  • numbered blobs;
  • words describing an individual action;
  • arrows linking the actions;
  • title.


  1. Start by drawing a large circle or boundary.
  2. Individuals activities (e.g. aaa, bbb, ccc, ddd, etc.) are placed within blobs.
  3. Link the blobs by arrows.
  4. Number the blobs according to the sequence implied by the root definition. More than one action may lead into a subsequent action.
  5. It is essential to write down the root definition as the title of the purposeful activity system.


  1. The first step is to decide upon the purposeful activity system to be modelled. Within the Soft Systems Methodology this is expressed as a root definition, which starts with the words: 'A system to/for/which…’.
  2. This root definition can be tested for its rigour through the guidelines of the mnemonic CATWOE or its derivatives. The letters stand for various aspects of the root definition which you should check. (See Root definition and its formulation.)
  3. One way to construct a conceptual model is to write down the actions (use verbs) that are logically implied by or already contained in your root definition. Write them down scattered about on a sheet of paper, and then try to put in the sequence of those activities as arrows between them. Find the activity which, logically, has to be done first, then draw an arrow to the one that has to be done next, and so on. This is much more difficult than it sounds, and your first or second attempts should be messy if you are really exploring the idea contained in your root definition. Another way to approach the task is to start with a very simple model and elaborate it gradually.
  4. The reason for taking so much effort to produce an ideal, theoretically perfect system, is that you can then compare it with what exists, in order to see where changes might be made. It is important to emphasize that the conceptual model is a statement of what is logically and necessarily implied by the definition. It is not a representation of what ought to exist, nor of what does exist in the real situation. The model should contain only those actions that would have to be carried out, and the order in which they would have to be carried out, if the system in your definition were to function.
  5. The conceptual model can also be tested by using measures of performance related to how the transformation represented by the purposeful activity might fail.


  • Checkland, P. B. and J. Scholes (1990). Soft Systems Methodology in Action. Chichester, John Wiley.
  • Midgley, G. and M. Reynolds (2001). Operational Research and Environmental Management: A New Agenda. Birmingham, Operational Research Society.


Key techniques for ECOSENSUS: Martin Reynolds