Polycentric Control and Requisite Variety

Only variety can destroy variety

This quote is a concise statement of Ashby's Law of Requisite Variety. Variety in this context refers to the complexity of a problem typically indexed using information statistics. And the important implication of Ashby's law for organizations is that to deal with complexity effectively, an organization must have the flexibility of thought and/or action that is comparable to the complexity of the problem. If an organization is less flexible than the variety of the problem, then there are opportunities that it will not be able to realize or threats that it will not be able to avoid. This concept is fairly intuitive in the context of competitive sports - for example the player who has the broader arsenal of shots (the greater variety) will consistently defeat a player with fewer capabilities. This is because the player with the broader arsenal will eventually find shots that the opponent can't counter. 

Following up on the idea of a control system with multiple layers with different time constants - one of the key implications of the polycentric control model is that none of the layers has the capacity to handle the requisite variety of any complex situation or operational domain. Thus, skill in any complex domain depends on the coupling and coordination between the layers. Each layer has its lane of expertise that allows it to deal with aspects of situations that cannot be adequately dealt with by the other layers. But no lane is completely independent - and activities in one lane shape the possibilities within each of the other lanes. The consequences of the between layer interactions can be that activities in each lane can facilitate or inhibit possibilities within the other layers. 

It is probably naive to think that there are only three layers, but as noted in the previous essay, the three layers shown in this figure parse the system in a way that aligns with numerous observations about the dynamics of cognitive systems and organizations from a wide range of disciplines (e.g., psychology, economics, sociology, control theory, and military science). Also - while I find the idea of filters tuned to different ranges of frequencies to be a useful analog for thinking about the layers - this is a loose analogy and not intended to be taken too literally (or quantitatively). I hope that this won't be too big a distraction to those who are not familiar with thinking in terms of the frequency domain. The goal for this essay is to introduce these three layers, and then following essays will spend more time considering the coupling or interactions across layers. 

The Mutual Adjustment or Skill-based Layer

The bottom layer in the diagram above will typically be sensitive to high frequency bandwidths (i.e., rapidly or suddenly changing events).  This represents the capacity to respond and to adapt quickly to sudden changes and surprises. In an individual this might be the motor control system; in a large organization this might be the front line workers who are most directly engaged in carrying out operations (in military terms this is the tactical level); and on an American football team this layer would reflect the actions of the players during play. Activity at this level typically involves implementing automatic processes or standard procedures to carry out the plans formulated at higher levels. However, this layer will also typically be required to improvise to deal with unexpected variability that was not anticipated in the planning or the development of the automatic processes, heuristics, and standard procedures. For highly dynamic, rapidly changing domains of operation the capacity to improvise at this level will be critical to resilience. For example, the ability of players on the football team to react intelligently during a 'broken play' when the quarterback is forced from the pocket by a defensive surprise. The biggest threat to stability at this level is the potential to chase the noise - that is, to waste energy following fads or spurious changes that are distractions and that do not lead to improvements or long term success. 

The Planning or Rule-based Layer

The middle layer in the diagram above will typically be tuned to intermediate level frequencies - that is, it integrates information over broader ranges of space and time than is possible at the lower level. This layer will be able to pick up event patterns and trends that require a broader perspective than is possible at a lower layer. In an individual, this would represent intentions and conscious heuristics, rules, and plans. In organizations, this is typically the function of managers and in emergency response and military organizations this would reflect the activities in an incident command center. For example, in an air operations center they might be generating plans for the next 6 - 10 hours of operations. In an American football team this layer would reflect the formulation of a game plan and then the communications between coaches (on the field and in the press boxes) and the quarterback to call a play or series of plays. And it will also include the replanning (e.g., at half-time), when deficiencies in the original game plan are discovered. This is the layer where it is possible to gain "top-sight" on a complex situation. However, it takes time to integrate all the information required for top-sight - too long for this layer to effectively respond to sudden surprises or momentary changes. For example, the receivers on a football team can't wait for the coaches to plan a new pass route when the original play breaks down and the quarterback is forced from the pocket. The other challenge to planning is that assumptions and expectations that are valid at the time a plan is formulated may not remain valid over the time it actually takes to implement the plan. 

The Standardization or Knowledge-based Layer 

The top layer in the diagram above will typically be tuned to very low frequencies, which provides the capacity to integrate over broad spans of time to identify reoccurring patterns, very slow trends, and principles (or invariants) that apply across many different events or situations. This layer reflects experience passed down from generation to generation through oral traditions, literature, and culture. For example, for the military domain this layer is informed by a long history that stretches back to Sun-Tzu and beyond. This layer is typically responsible for developing standard practices and expectations - that include specifying operational principles that can be applied successfully across a broad range of situations and then inculcating those practices into the organization through training (e.g., deliberate practice). In an individual, this layer would typically be associated with a persons value system and the enduring patterns that are typically identified as their personality. This system does not directly control action - but it shapes the planning and actions of an individual in general ways that will be apparent across broadly different situations. In an organization, this layer reflects what is often referred to as its culture. In operation - this layer typically involves the top-level leaders in an organization who set the general goals and expectations for the organization and might also specify the command intent as a guide to a specific operation. 

Interactions 

To push the filtering analogy a bit - a linking assumption is that the requisite variety of a complex problem domain will involve signals that are spread across the full range of frequencies. So, a filter that is tuned to a certain bandwidth will miss signals outside that bandwidth. A key factor that will limit the bandwidth of any filter is the effective time constant or the lags associated with feedback.  So - just based on the fact that the time to collect, process and act on information will be necessarily different for the different layers in the polycentric control system suggests that the bandwidth limits for each layer will be different. But of course, there are many other factors that will impact what signals can be seen at each layer (e.g., trust). The main point is that people at the top layer of the polycentric control system (e.g., the C-suite) will have access to information not available to the other layers. But similarly, each of the other layers will have access to information that is not available to the C-suite or to the other layer.  Thus - coordination between layers is necessary to meet the demands of Ashby's law.  The variety of the whole is always greater than the variety of any single layer. Or more simply - each layer offers a unique and potentially valuable perspective towards addressing the operational demands. 

Success ultimately depends on coupling and coordination across the three layers. Each layer has the capacity to complement the other layers and fill in information gaps in the other layers. However, the layers can also function in ways that complicate and inhibit capabilities at the other layers. A recurring theme with respect to a layer getting out of its lane in ways that inhibit capabilities at the other layers are the problems of micro-management or of authoritarian, centralized organizations. As Fredrick von Hayek's has observed with respect to managing economies - no matter how well-intended or intelligent a centralize management organization is - it simply takes too long to collect and make sense of all the potentially relevant information. In essence, the decisions will always be a day late and a dollar short. A centralized control agency is far too sluggish to productively manage large economies. On the other hand, he also recognizes that for free markets to function well, there needs to be effective communication systems and market constraints that entail a certain degree of top-down constraint. When the balance is right - the free market system can self-organize in highly intelligent ways. In the military, the construct of Mission Command reflects an alternative to micro-management that emphasizes the importance of clearly communicating intent (minimal top down constraint) and then empowering lower levels in the organization to work out the operational and tactical details as required by the situation demands that could not have been anticipated in advance.

With respect to Ashby's Law the challenge for organizations (and organisms) is to distribute authority and responsibilities across the layers in a way that is commensurate with the access to information at each of the layers. 

The goal for this essay was to begin differentiating the functions of the separate layers. However, the major systems principle to consider with regards to polycentric control is that the individual layers can only be fully understood or appreciated in the context of the whole.  With respect to functioning successfully in a complex world - no single layer can effectively deal with the demands of requisite variety without the support of the other layers. And ultimately, the power (or weakness) of the whole will emerge from interactions across the layers.