Theory of Constraints crash course by Philip Marris

Описание: Philip Marris delivers a "Crash Course on the Theory of Constraints".

Eliyahu Goldratt’s book “The Goal” is quite an unusual novel. Despite being decades old, it remains a bestseller, available in 29 languages. [Note: Over 10 million copies sold in 2025.]

Although it was written before the internet, before mobile phones, and even before the fall of the Berlin Wall, its relevance remains striking. The principles apply broadly, not only to manufacturing but also to fields like healthcare, IT, and general business management. While the novel’s story revolves around a factory producing engines, its lessons extend far beyond the shop floor.

For those in the DevOps and Lean Manufacturing communities, The Goal is often required reading. It introduces the Theory of Constraints (TOC), a framework that helps organizations identify and manage bottlenecks in their processes.

The Theory of Constraints is based on a simple yet powerful idea: every system has a bottleneck—a constraint that limits its overall capacity. Many organizations try to balance work evenly across departments, allocating resources based on estimated needs. However, Goldratt challenged this approach, arguing that in a fast-changing world, perfect balance is unrealistic.

This concept was somewhat applicable in early industrial settings, such as Ford’s Model T production lines. However, in today’s rapidly evolving markets, businesses cannot assume an even distribution of work.

The reality is that while market demands and technologies evolve rapidly, an organization’s ability to adjust its capacity lags behind. Hiring, training, and implementing new systems take time, making it impossible to adapt instantly. As a result, workload imbalances are inevitable.

A key principle of TOC is that a system’s overall output is determined by its constraint. If the bottleneck stops for a day, the entire system loses a day’s output. However, if a non-bottleneck process stops, the system can usually recover.

One major mistake businesses make is investing in improvements that do not address the constraint. The majority of improvement projects will target non-bottleneck areas, yielding no real gains.
Furthermore, TOC suggests that full utilization of all resources is not always beneficial. Overloading non-constraints creates unnecessary work-in-progress, clogging the system. Instead of measuring individual efficiency, businesses should focus on whether each task contributes to the system’s success.

The Drum-Buffer-Rope Method
Goldratt introduced the Drum-Buffer-Rope method as a structured way to manage constraints:
• Drum – The constraint dictates the pace of work.
• Buffer – Ensures that work reaches the constraint on time, preventing disruptions.
• Rope – Regulates the flow of work, preventing excess buildup before the constraint.

5 Steps to Continuous Improvement
TOC follows five key steps for ongoing improvement:
1. Identify the constraint – Find the system’s bottleneck.
2. Exploit the constraint – Maximize efficiency at the bottleneck with minimal investment.
3. Subordinate everything else – Align other processes to support the constraint.
4. Elevate the constraint – If necessary, invest in expanding its capacity.
5. Repeat the process – Once the constraint is resolved, identify the next one.

Traditionally, TOC focuses on identifying bottlenecks and addressing them. However, at Marris Consulting, we take a different approach. Instead of constantly reacting to emerging constraints, we believe organizations should proactively choose where their bottleneck should be.
Since perfect balance is unattainable, businesses should control their constraint rather than let it develop randomly. By strategically positioning and managing their constraint, organizations can achieve greater stability and predictability. Instead of endlessly hunting for bottlenecks, ask: Where should my constraint be? If we accept that perfect balance is no longer possible, why not make a deliberate decision about the location of your bottleneck? This is the Marris Consulting perspective—an evolution of the traditional Theory of Constraints that enables businesses to operate more efficiently in today’s dynamic world.

PRODUCTION NOTE
This video is from the opening of a Critical Chain Project Management Training Course in 2017.

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Marris Consulting is a management consulting firm dedicated to manufacturing companies. We are based in Paris, France but we work globally.

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