Soft Systems Methodology

SSM is presented in a series of 7 steps though it’s not meant to be followed in a linear fashion. Stages may be skipped, refined, iterated or followed depending on the peculiarities of the situation. The analyst moves from the real world of gathering information about the situation (elicitation), to the model world of systems thinking (analysis) and back to the real world to verify the requirements (verification).

Stages 1 & 2: 

Problem Situation Unstructured – This is where the analyst is faced with the messy situation and he decides what exactly is to be explored. He tries to make sense of it by arranging interviews with stakeholders, conducting observation sessions, document analysis and generally gathering all the data that is needed to understand the situation

Problem Situation Expressed – At this point, the analyst has gathered enough information to express the situation in the form of pictures. A rich picture is a graphical representation of the situation that attempts to capture both the subtle and the overt. Power structures, communication lines, processes, interest groups and differing world views (Weltanschuung) are captured.  

Checkland provides a guideline of what can be included in a rich picture: Structure, processes, people, concerns, conflict and climate.

Here is an example of a rich picture.

Rich Picture Source:

It is a snapshot of the problematic situation that reveals differing perspectives, and captures the formal and informal aspects of the problem situation. 

Stage 3: Through stages 1 and 2, the analyst proposes a root definition of a system that is relevant to solving the problem. Here, the analyst enters the world of systems. A root definition is usually framed as:

A system to do X by means of Y to achieve Z.

Many root definitions of the relevant system can be developed based on as many world views (Weltanschuung) as there are. The analyst should however, identify the “primary task” root definition which represents the official task of the system. A popular mnemonic called CATWOE, framed by Checkland, is used for constructing the root definition. It is elaborated as follows:

C – Customers: beneficiaries or victims of the proposed system

A – Actors: participants in the human activity system

T – Transformation: means through which inputs become outputs

W – Weltanschuung: Particular way of viewing the situation that makes the root definition meaningful

O – Owner: stakeholder with prime concern for the system. He has the power to make the system cease to exist

E – Environmental Constraints: Features of the environment that affect the operation of the system

A practical example of a root definition, starting with the CATWOE is as follows:

C – Customers

A – Planning Specialists

T – Forecasts from salesmen are transformed into a material requirements plan

W – Aggregation of forecasts from salesmen is a means of achieving an accurate materials requirements plan

O – Top Management

E – Specified Data format, Available technology

Now, this CATWOE Analysis may yield a Root Definition such as: a company owned system to generate a material requirements plan (X) by collecting sales forecast from field agents (Y) in accordance with prescribed data standards in order to meet customer demand, increase company revenue and promote company-wide collaboration.

Stage 4: The analyst forms a model of activity for each root definition.

Here, the analyst proposes a list of verbs comprising activities necessary for the transformation. The model is only a tool for facilitating discussions with stakeholders and is not an end in itself; it should be used as a tool for raising questions and interacting with stakeholders until understanding is achieved. The iterative nature of SSM allows the analyst to draw a model, discuss its implications with stakeholders and then redraw as needed.

Running through as many models as possible, allows the analyst to compare differing world views and identify contradictions/recurring themes between models. Basically, the more models analysts build, the more they’re able to understand other perspectives and defend their positions in front of stakeholders.

Stage 5: Comparison of model with real life

In this stage, the analyst compares the model with what happens in real life. The objective is to highlight any differences, complexities, contradictions and inadequacies of reality.

Stage 6: Feasible, desirable change

The objective at this point is to determine which changes can be implemented. Any recommended change must be compatible with the organizational culture and acceptable to all participants. While a peaceful negotiation will not result in a 100% satisfaction of all stakeholders, it will ensure that a solution that all parties can live with is identified.

Stage 7: Action is taken to improve the problem situation

One of the advantages of SSM is that it allows the analyst address key perspectives of how a system should work by understanding their implications and reintegrating these perspectives to provide a practical solution to business problems.

This post is based on Soft Systems Methodology in Action by Peter Checkland