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An Introduction to the Theory of Constraints

Decision Making – Focus on the Goal

Almost every manager is aware of Pareto’s law, the important few – the trivial many which is often thought of as the 80/20 rule. 80% of results are generated by 20% of the actions. To improve your effectiveness, one only need to focus on the 20% and you’ll get almost all of the results (80%). This simple truism is generally true, but not true in systems where there is strong dependency relationship between the entities. In these types of systems, the rule is closer to 99/1. 99% are relatively trivial and only 1% are important. 

This is the world of organizations.

The ToC is the science of making decisions in that world. 

It starts with the articulation of the Goal. The purpose of the organization.

Throughout the literature, the goal of the enterprise is stated as to make more money now, and in the future. This is rooted in the idea of ownership and the rights of owners to establish the direction of the enterprises in which they have an interest. Who gets to establish the purpose of any system? Its owners. For companies that are publicly held, it is clear that the motivation of its owners (stockholders) is profit. Therefore, the enterprise must be directed towards that end.

That’s not to say that the pursuit of increasing profit is exclusive of anything else. The goal is to make money in the future as well. In order to fulfill this aspect of the goal, we recognize that are boundary conditions – necessary conditions that must be met in order to achieve the goal. You can’t mistreat your workers for long, it will sacrifice the future. You can’t disobey the environmental regulations for long, or your profit will be impacted through fines, negative market response, etc.

This goal (making money) is not universal. Charities, governments, churches, schools are (generally) not directed to making more money now and in the future. Maybe your private company is not directed towards that goal. That’s fine. ToC is not about the goal; it’s about pointing the organization to achieve the goal. What is important is that the goal is verbalized, and a measurement is in place to determine whether or not you are getting closer to it. If you’re a non-profit, the goal is not measured in money, but money is a necessary condition to achieve that goal.

The objective of using ToC is to improve your capabilities to move you closer to achieving your goal. More money now and in the future, fewer people without homes now and in the future, mores students better prepared to enter the workforce now an in the future, etc. Your efforts as a manager and leader are to move the organization closer to its goal. Now and in the future. 

Marking the distinction between THE goal and necessary conditions is the first step to focusing. As a matter of focus, the necessary conditions are those factors that are monitored, but not improved unless there is some violation. 

The goal is your “true north” or your chosen strategy to achieve that true north. The necessary conditions are the boundaries. The distinction between the two is found when you satisfy that necessary condition. For example, cash flow. If you have enough, it is not a matter that requires full attention. If you don’t enough, nothing else matters, not even the goal! 

A Chain is Only as Strong as its Weakest Link

Achieving the Goal is a process, subject to dependency and variation. In order to make money, one must have a product, a customer to buy, a system to deliver, and then get paid. How many people does it take to disrupt that process?  Just one. There’s your dependency. We know Murphy lives, so there is your variation.

Making money – achieving your goal is like managing a chain, where each link (action) and resource (strength) is connected to another. We all know that the strength of the chain is determined by its weakest link. Organizations are like chains. There is always the weakest link. The challenge is identifying that link, then moving the organization to strengthen that link. Since the strength of the chain is always determined by the weakest link, there will always be one, if that is strengthened, there will still be a weakest link.  

That weakest link is the Constraint. It determines your profit, your return on investment, your performance in your market. If you don’t know where it is, you are shooting in the dark. Serious pursuit of the Goal implies serious pursuit and breaking of the Constraint. Putting your attention and resources to improve in other places may improve the local situation but will not improve the global situation.

Since the Constraint only exists in the context of its goal, actively breaking the organization’s constraint or moving the it to a ‘better’ location moves the organization closer to achieving its goal (more and more).

A Bottleneck is Not the Constraint

Often, we see our progress blocked by scarcity; not enough resources to accommodate demand. It may seem like the constraint bounces around the organization without rhyme or reason. This is the evidence that you do not have an internal resource Constraint, but rather, your organization does not know where the Constraint lies and thus, cannot react to it. Bottlenecks are temporary, the real Constraint is difficult to move. It’s expensive. Scarce. 

Engines of Disharmony / the Core Conflict

In the early development of the ToC, the Constraint was to be considered a physical thing, like a machine or some capability. This evolved into thinking of the Constraint is a set of rules or policies that govern the utilization of physical resources.  This realization gave rise to the search for a method to identify these ‘erroneous’ policies, and the Thinking Processes were developed.

Over time, ToC practitioners found that erroneous (sub-optimal) policies are a developed as a reaction to resolve a conflict in the system. I.e., short term action vs. long term action, or satisfying customers vs. satisfying shareholders. Typically, the resolutions are compromises between necessary conditions, sacrificing a bit of each to find an acceptable solution. As organizations become more and more complex, these compromises become the fabric of how the organization is run, and the compromises also become more complex. 

These conflicts, where there is a sacrifice of a necessary condition, are thus related to each other, and can be traced to a single, core conflict. Many problems can be traced to this unresolved conflict.  This conflict and the resulting compromises become the Engines of Disharmony, creating friction in the organization, blocking progress. 

This core conflict becomes the true Constraint. Identifying and resolving that conflict is the holy grail of a ToC based strategy.

Strategic Implications of the Theory of Constraints

The strength of any chain is determined by its weakest link. No chain is infinitely strong, therefore the strength of even the strongest chain is still determined by its weakest link.

Your organization will always be constrained.

Strategists should not be chasing the weakest link; they must decide where that link will be. Your strategy and tactics are to move the Constraint to a location where it propels your organization closer to its Goal now, and in the future. You will be anticipating the movement of the Constraint and building supporting structures to support the sustainment of the location, hopefully before it moves.

Breaking Constraints

Is the Constraint internal to the organization or external? Is it the market size (demand) or an internal capability that prevents you from satisfying all the demand?

I’ll show later that the Viable Vision[1] strategies are built on developing a decisive competitive capability (edge) or improving an area of operation, then exploiting this new capability to gain market share. For example, if there is excess production capacity (the desired Constraint) or underserved market(s), a strategy would be built focusing on customer facing activities like more sales activity (the current bottleneck) in a certain market segment or new products (a Constraint, but not the one that is wanted) that create more demand for segments where there is opportunity. 

The strategy could be driven to achieving a certain objective, like domination of a market, or introducing a new technology. The execution of the strategy would be based on moving the Constraint from one area of the company, like sales capacity to another area of the company, say, product development. 

Understanding the Constraint today versus the desired location helps decision makers choose the best alternatives, moving the organization in a practical way, closer and closer to its goal.

The Applications of the Theory of Constraints

The applications or solutions of the Theory of Constraints are:

  • The 5 Focusing Steps
  • Drum Buffer Rope, a production scheduling technique
  • ToC measurement systems (Throughput, Inventory, Operating Expense), management financial decision making
  • Critical Chain Project Management, project scheduling and execution
  • Demand-Pull Replenishment (the Distribution Solution)
  • ToC in Sales & Marketing
  • The Thinking Processes, analyzing, creating solutions, and implementation for complex systems

From a strategic standpoint, we don’t really need to know the details of these solutions, only the rough contours and effects of them.

I want to mention that as we (in the ToC community) understood these applications better over time, we also understood the ToC better. The ToC wasn’t created or even named until a few years after the Drum Buffer Rope solution was developed. Over the years, we struggled with the essence of ToC, and that has probably contributed to its lack of recognition as a tool for strategists. 

5 Focusing Steps

The Focusing Steps of ToC.  A checklist of sorts.

  1. IDENTIFY the systems constraint.
  2. Decide how to EXPLOIT the constraint. Maximize its use.
  3. SUBORDINATE everything else to the decisions made to your exploitation decisions. Ensure the 99% does not get in the way of the 1%.
  4. If, in the prior steps, the constraint has not been broken, ELEVATE the system’s constraint.
  5. Go Back to step #1.

This may seem a bit tactical – like you’re chasing your constraint all over in infinite loops. When you first apply the ToC, you’ll find yourself in that mode. As you mature in the use of the ToC, you’ll find using these steps in a more conceptual manner as you develop your strategy, choosing the Constraint rather than chasing it. 

Even so, it does imply a sequence to attacking the Constraint. Know where it is. Don’t waste it. Ensure no other resources are preventing its full use. Then get more, break the Constraint. Find the new one.

Strategically, the focusing steps help you sort the types and sequence of actions you’ll be taking. More on using these in a strategic context later.

Drum Buffer Rope

The main idea of drum buffer rope (DBR) is to find the Constraint in a sub-system – production, then follow the focusing steps. This is what happened in the book, The Goal. 

During this process, the characters redefined operational efficiency and showed the impracticality of monitoring everything during execution and introduces the concept of Time Buffers.

What the DBR scheduling method does (over other models of production management) is significantly improve operational efficiency, reduce production lead times and improve delivery reliability.

ToC Measurement Systems (Throughput, Inventory, Operating Expense) 

Also introduced in The Goal, T, I, & OE were used as simplified financial metrics for decision making. What the system accomplishes is eliminate distortions in decision making over cost allocation methods. The metrics for decision making improve alignment in decisions, resulting in better resource allocation throughout the organization.

Critical Chain Project Management

The method of planning, scheduling, and execution of projects is a local solution (projects or portfolios of projects) that identify the constraint as the longest chain of resources and tasks, with the Goal being the delivery of the project.  The methodology further refines the use of time buffers in processes with greater uncertainty and variation.

What CCPM does is dramatically reduce the time to deliver projects, improve productivity and delivery reliability. 

Demand-Pull Replenishment

Sometimes called the “Distribution Solution” of the ToC, this solution combines time buffering management with a demand-based replenishment mechanism to improve availability with less inventory investment. Often a 50% improvement over traditional methods, it solves the bullwhip effect found in supply chains. 

As with the other solutions, the supply chain is dealt with as a sub-system, with the Constraint being shelf space, and the Goal being sales (of SKUs).

ToC in Sales and Marketing

This application is probably the most strategic in the sense that it considers the needs of the customers in other dimensions besides delivery reliability. When the Constraint is in the market, internal capabilities take a back seat. The application is broken into:

  • The Un-refusable Offer (sometimes called the Mafia Offer) 
  • The Layers of Resistance (sells the offer)

The definition of Un-refusable Offer (URO)is one that is so compelling, has so much value, is so good, that customers cannot say no when presented with the offer. This offer would be created by having a deep understanding the customer, the industry, and identifying the core problems. 

The unique feature of a URO is that it is a complete solution that solves the customers‘ core problem as it relates to doing business within their industry. It is not a restatement of the unique value proposition, although it most certainly fits that definition. Creating a URO typically requires that a supplier of the offer do something different (e.g., make operational improvements) to address the customers’ core problem. 

The Layers of Resistance is a framework for selling the offer and is often used on its own to create buy in to a new idea or solution. The Layers are:

  1. We don’t agree on the problem being addressed
  2. We don’t agree on the direction of the solution
  3. We don’t agree the solution solves the problem
  4. We see that the solution, if implemented, causes negative effects
  5. We see obstacles blocking a realistic implementation of the proposed solution
  6. Fear of the unknown

The steps are to be accomplished in sequence to gain agreement or buy in to the proposed solution. 

What is thought of as resistance becomes a tool for managing organizational change (or selling a solution) to systematically objections and obtain buy-in. 

The Questions on Technology are thematically similar.

  • What is the power (capability) of the new technology?
  • What limitation does it diminish?
  • What are the old rules that supported the limitation?
  • What are the new rules that should be used now with the new capability?
  • What technology changes are required to support?
  • How to cause the change?

The ToC (constraint busting) has been applied to the sales process itself, breaking the Constraint of sales staff interaction with the customer, enabling massive increases in sales productivity.  This approach breaks a fundamental assumption in sales process engineering, that sales should be the sole responsibility of autonomous agents. 

What ToC does for sales and marketing is to identify ‘blue ocean’ strategies to find new market opportunities and re-think the manner in which the solution is sold to the customer; from articulation of value to communicating that value to customers and markets.

The Thinking Processes (TP)

The objective of the TP is to reliably answer the question of where to focus. It makes clear distinctions between causes and effects, exposes hidden assumptions and identifies the relationships among them. Typically used when one is developing a deep understanding of a system with an eye towards improving it. 

The TP is a set of tools answer the 3 questions of change.

  • What to change?  Defining the core problem – the elements that are the causes of the undesirable effects (symptoms). 
  • What to change to? Defining the changes to be introduced to eliminate the current undesirable effects without creating new ones.
  • How to cause the change? Mapping the actions from the current state to the future state without creating new problems.

The TP consists of the Current Reality Tree and Evaporating Cloud, which is devoted to answering the first question. The Future Reality Tree and Prerequisite Trees are used to answer the second, and the Transition Tree is used to answer the third.

A special category of the TP is devoted to the most recent development, the Strategy & Tactics Tree. It is used most frequently to answer the 3rd question or in situations where the first 2 questions are not necessarily deeply analyzed. 

These capabilities are the typical starting point of ToC based strategy. Anyone can break a single constraint or implement a single solution. The strategy dictates how to create, capitalize upon, then maintain that decisive competitive edge.


Goldratt, Eliyahu & Jeff Cox, (1984), The Goal; Excellence in Manufacturing, North River Press 

Goldratt, Eliyahu, (2011), Theory of Constraints Handbook Chapter 1 Introduction to ToC, McGraw Hill 

Goldratt, Eliyahu, (2012), The Gestalt of ToC Part 1, YouTube

Goldratt, Eliyahu, (2017), Engines of Disharmony, YouTube

Cox III, James F., Lynn H. Boyd, Timothy T. Sullivan, Richard A. Reid, and Brad Cartier, 2012, The Theory of Constraints International Certification Organization Dictionary, Second Edition,

Roff-Marsh, Justin, 2015, The Machine: A Radical Approach to the Design of the Sales Function (Book 1), Independently Published

Goldratt, Eliyahu, (2008), The Every-Flourishing Company – Part One

Goldratt, Eliyahu, (2008), The Every-Flourishing Company – Part Two,

Barnad, Alan, (2016), Applying Theory of Constraints to developing Business Strategy,

[1] Viable Vision is a strategy with the objective of converting a firm to ever-flourishing. We’ll discuss the different strategy templates associated with the Viable Vision approach in later chapters.

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