Viable Systems Model (VSM)

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The Viable Systems Model (VSM), developed by Stafford Beer, is an organizational representation of the elements and interactions considered essential for any system to be viable or autonomous. A viable system being one that is organized and operates in a manner such as to survive in its changing environment. Adaptability is one of the prime features of systems that survive. (Adapted from Wikipedia)

The VSM builds heavily on Ross Ashby's Law of Requisite Variety (see Systems Laws #3) and is a way to organize a system so as to make it respect this law whatever the way it may be viewed.

Fig. 1 - Viable Systems Model (VSM) [Source]




As depicted in Fig. 1 a viable system is a cooperative interaction among five functional subsystems.

  • System 1. Elements concerned with performing the key transformations of the organization.
  • System 2. Information channels that enable System 1 elements to communicate between each other and allow System 3 to monitor and co-ordinate System 1 activities.
  • System 3. Consists of structures and controls that establish rules, resources, rights, and responsibilities of System 1 and provides an interface with Systems 4 and 5.
  • System 4. Elements which look outward to the environment endeavoring to understand how the organization needs to adapt to remain viable.
  • System 5. Creates policy decisions within the organization as a whole to balance demands from different organizations and provides direction for the organization as a whole.

A key aspect of the Viable Systems Model (VSM) is that it is a recursive structure. That being that each system within the viable systems model is also a viable system.

  • Algedonic Alerts. Alarms and rewards that escalate through levels of recursion when actual performance fails or exceeds capability. This signalling goes along communication channels detailed below.

Communication channels

Not represented on the preceding diagram, there are 6 communication channels. Worth noting is that the communication channels need to have requisite variety too.

  • C1 between sub-parts of the environment (represented on the diagram as overlapping zones)
  • C2 is the communication channel of S3* (audits)
  • C3 is the communication channel between each S1, allowing them to autonomously coordinate their actions (exchanges between departments goes here for instance)
  • C4 goes from S3 to all S1s and vehiculates the regulatory and mandatory informations
  • C5 between S3 and S1s is for negociated informations (budget goes along this channel for instance)
  • C6 allows exchange of stability information used by S2


The VSM is usually used for two purposes:

  • as a diagnostic tool where an organization is compared to the model to identify:
    • part of the VSM that the organization lacks, thereby threatening its viability
    • part of the organization not present in the VSM, raising the question of their usefulness for viability
  • as a model to help (re-)design an organization

Unfolding of the VSM on an organization need not be done exclusively from a hierarchical level (though this might be seen as the easiest way to do so). Other complexity drivers may be considered: time, geography, markets/customers, technologies, etc.

Note that the Viable Systems Model is a model, not a method. While you can design and create a Viable Systems Model you can't do VSM per se, though you can evaluate an organization as to the extent to which it operates consistent with the Viable Systems Model. In the Jackson Framework the Viable System Model is viewed as an approach for improving goal seeking and viability.




Online Papers


Additional Resources
Systems Thinking World Discussions * Gene Bellinger
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