5.2.6 Soft System Methodology (SSM)

Soft Systems Methodology is an approach to inquiry into problem situations perceived to exist in the real world (Checkland and Scholes, 1990:18). It originates from the more general field of Systems Engineering, but have departed from the tradition of "hard" systems thinking (in which the perceived reality is considered systemic and inquiry systematic) into what is referred to as "soft" systems thinking (where perceived reality is problematic and inquiry is systemic). In their discussion of SSM and information systems development, Hirschheim et al. (1995:242) point out that SSM
"is a framework which does not force or lead the systems analyst to a particular 'solution', rather to an understanding."
SSM has evolved through several versions, with (Checkland, 1981) as the most widely cited. The presentation in this section is taken from a revised version of SSM found in (Checkland and Scholes, 1990).

The process of SSM is illustrated in figure 5.6. A real world problem situation is perceived to exist. This situation has a particular history, providing a richer basis for understanding the situation. Actors (would-be improvers of the problem situation in) using SSM will follow two distinct, but integrated streams of analysis: A logic-based and a cultural.

Figure 5.6: The process of SSM (from Checkland and Scholes, 1990:29)

In the logic-based stream, actors develop a number of descriptions of so-called relevant systems, being possible human activity systems that match the problem situation. These are modeled and compared to the perceived situation. Comparisons serve to structure discussions about change.

Relevant systems are named in terms of root definitions. A root definition is a sentence expressed in natural language, consisting of elements in accordance with the mnemonic CATWOE:

Related to enterprise modeling, a root definition for a hypothetical human activity system might be "a management controlled system to develop enterprise models of the entire corporation through a consultation approach in order to ensure holistic understanding and overview of unprofitable business units before business process reengineering.

The CATWOE of this root definition is Customer = management, Actors = consultants, Transformation = management without overview => management with overview, Weltanschauung = enterprise models can ensure holistic understanding, Owners = management, and Environmental constraints = there will be a reengineering of business processes.

In the stream of cultural analysis, there are three main examinations of the problem situation:

  1. Intervention analysis, i.e., analysis and reflection upon of the application of SSM to the problem situation. "Rich pictures" (informal drawings) are developed.
  2. Social system analysis, focusing on roles, norms and values in a problem situation.
  3. Political system analysis, answering questions related to power distribution in the problem situation.
Based on comparison from the logical-based stream and the three analyses in the cultural stream, one choose to go for changes that are systemically desirable and culturally feasible to implement. The last "stage" is action in favor of making changes.

The relevance of SSM to enterprise modeling is the way SSM concerns construction and communication of perceived realities through development of model-like artifacts. Main focus is developing holistic (systemic) understanding of the problem situation, which coincides with the focus on enterprise modeling in this thesis. SSM focuses on the sense-making part of modeling and not so much on the representation, manifestation and distribution.

SSM is developed for problem situations that require making sense of any reality. Hence, it is appropriate for modeling work of all types.

All artifacts developed in accordance with SSM principles are informal. There are no predefined vocabulary, syntax or semantics, except for the CATWOE (but this is still informal). Hence, formal models are not in focus of SSM. The enterprise modeling process is, on the other hand, treated in-depth in SSM. Activities related to modeling include the three types of cultural analysis and development of conceptual models as part of logic-based analysis.

SSM is clearly constructivistic, as also assessed by Krogstie (1995:60). Human actors are considered to be subjective beings with different worldviews giving rise to different interpretations of their perceived realities. A purpose of SSM is to support the process of creating models of these different interpretations and thereby make them subject to reflection and debate (Checkland and Scholes, 1990:27).