Jon Miller, partner at the Kaizen Institute and founder of the Gemba Academy, argues that lean needs to develop itself as a scientific method in order to improve both its reputation and its own ability to function as efficiently as it can.

Some view lean as a set of broadly applicable principles and methods for business excellence, originating in Toyota’s supply chain innovations. I view lean as a type of organisational medicine. Lean is a medical practice applied not directly to individuals but to groups of people, to organisations such as businesses, government offices, hospitals, schools, charities and so forth.

Organisations have a purpose, whether it is making money, spending money for the benefit of a cause. The health of an organisation can be measured in various ways such as profit, growth of membership or expansion of services to the community. The practice of lean helps people and organisations to achieve their mission and purpose with less effort, less strain and more reliably by design rather than by luck. Not to be forgotten an important characteristic of lean as organisational medicine is that the health of an organisation must also be measured in the physical and psychological health of its members. That is an indirect but integral effect of the organisational medical practice called lean.

There are parallels to medical practice on the human body in the way that lean is applied to organisations as medicine. The jidoka or autonomation pillar of lean was likened to the autonomous

system by the Japanese creators of the Toyota Production System. The human autonomous nervous system allows us to feel pain and recoil without thinking. The idea of jidoka was to create an autonomous nervous system within an operation: processes capable of sensing pain in the form of defective products or human errors, immediately alerting the brain in the form of the area team leader, to take action. For machines that operate on automatic cycle, jidoka added the capability to be “autonomous” in stopping when an error occurred, rather than continuing to create defective products. Just as when a human body is in danger of damage and infection when it ceases to feel or respond to pain, an organisation that cannot or chooses not to feel its pains, grows ill.

The second pillar of lean is called “just in time” and is built on the pull, flow and takt time. This is analogous to the human circulatory system. In order to live, we breathe (pull) air in, which supplies oxygen to our blood, which flows at the beat of the heart (takt time). When we exert ourselves by running, our heart beats faster and we must pull more often to maintain the flow. We do not take fewer larger breaths, which would be batching, because our body needs a constant supply of oxygen and removal of carbon dioxide. The same is true within organisations. A frequent and correctly-sized, customer-paced exchange of information, materials and cash helps to maintains organisational health.

The human body also requires a schedule and rhythm levelled and averaged over time. Illness results from overburden on our system. This can be from too much or too little work, food, sleep, physical exercise, or from consuming more toxins than our bodies can neutralise at one time. Bodies need a balance of calorie consumption, physical activity, work, play and rest in order to be healthy and have functional lives among other humans. Businesses and organisations must live within harmony of other organisations in their supply chain, healthy human lives tend to unfold when in harmony the rhythms of family and society. When a business is extremely busy at the end of the month but idle at the beginning of the month, it suffers losses and limits its ability to be of better service to customers. The desired condition of a level and average schedule is called heijunka in Japanese, and represents the foundation of the pillars.

In exploring the notion of “lean as a science” it is therefore interesting to ask, “how well does lean work as organisational medicine?” I assert that at the current moment, lean works about as well as folk medicine. Modern medicine began as folk medicine, the result of centuries of trial and error with the periodic advancements in our scientific understanding of health, or technological invention. Folk medicine is said to differ from modern medicine in that, to a greater degree than modern medicine, it includes remedies not proven to work, even for those proven to work we haven’t always shown how. It is interesting to note that while folk medicine may include remedies that will not survive the scrutiny of scientific inquiry, it also includes those at or beyond the current boundary of scientific explanation.

There are parallels to lean. We can call lean a practice-based school of management thought. The theorists are late-comers to the game. The factory-based invention of the lean model we know as the Toyota Production System, or Toyota Way, was not documented or even properly studied academically for decades. We can say that it was passed on as a collection of folk remedies within the society that was the Toyota group of companies. As with folk remedies that have worked well enough within a certain community for generations, the lean system transplanted to different countries, industries or organisational cultures has not always been a success. This is not because the remedies themselves are inadequate, but rather because we took lean as a package of wonder drugs, rather than as a lifestyle and a set of habits. Nor did lean practitioners always properly diagnose the patient before offering a remedy.

There is no argument that the history and much of the current practice of lean is deeply grounded in the scientific method. There are algorithms and mathematical proofs, natural and scientific laws which underpin the superiority of designing our organisations with autonomous nervous systems, circulatory systems, and following natural rhythms. Lean is testable, and unlike some folk remedies, does not require faith in order for it to work. But the way we talk about lean today is far from scientific.

First and most troubling, we lack a definition of lean agreed as good, necessary and sufficient by the community of lean practitioners. In fact, there is not even explicit agreement that a common definition is necessary, that lean can somehow be defined in highly personal and context-specific terms. It is true that health, wellness and happiness may be highly personal attributes, defined differently by social context. But there is broad and general agreement on what we mean by injury, illness and death. The purpose of lean is to forestall these major and minor organisational illnesses as long as possible, so we can pursue whatever is our purpose in our personal or organisational lives. Lean should be preventative, not exploratory surgery, with clear and explicit prescription whenever possible.

“An apple a day keeps the doctor away” is an old saying that illustrates preventive wisdom of folk medicine long before medical science was able to articulate why eating more fruits and vegetables was healthy. Folk medicine tends toward the preventive. This was by necessity, since most people did not have modern hospitals nearby and could not plan on recovering from serious illness. Taking small preventative steps was more efficient than having to suffer the time and energy spent on a cure. Indeed, the greatest advances in lifespans, human health and wellness over the past few centuries have not come from medical technology, pharmaceuticals and surgical techniques; they have come from measures such as removal of sewage from our streets, purifying our drinking water, pasteurisation, removing deficiencies from our diets, and the recognition and reduction of bacterial infections.

These are preventive measures. Lean adds no value when it is mainly surgical, it must be preventive. Kaizen events to rapidly fix broken processes are no doubt necessary. There is a phase when lean must be implemented, the patient stabilised. This should be done as quickly and intensively as possible to allow the patient to regain health and prevent future illnesses through practices that strengthen the autonomous nervous system and the circulatory system.

To be clear, modern medicine should not be ignored in favour of romanticised folk medicine. Neither should lean be the answer to all organisational problems, at the expense of simpler proven solutions. While folk medicine and modern medicine may tend to eye each other somewhat warily, lean should be open to all ideas that promote good organisational and personal health.

Today, we are not yet at this point due to the fact that most practitioners lack sufficient mastery to go beyond their chosen framework, routine or doctrine. There are other common risks and benefits of folk medicine that are instructive to how lean is practiced today. Risks shared by the practices of both lean and folk medicine include:

  • Quackery. Too often lean practitioners have about as much accreditation as practitioners of folk medicine.
  • Faith healing. Charismatic leaders may develop a strong belief in the remedy and close their minds to proven alternate methods, at the expense of the health of their followers, employees or family members.
  • Chance. Eager to prove results, we fail to check if recovery was due to the prescribed remedy or due to regression to the mean, back towards normal health.
  • Style over substance. When the knowledge is passed down for several generations without deep understanding, the result is a superficial, ritualistic, bureaucratic and ineffective application of the remedy.

Part of the backlash against lean tools and the trend towards organisational learning, coaching and problem solving has been due to taking improper doses of the remedy.

For example, flow is a common folk remedy of lean said to reduce inventory, improve quality, shorten lead-times and improve productivity. Indeed it does, when all that ails one’s organisation is a lack of flow. But in reality it is necessary to diagnose the ills by examining the system broadly; including pull, flow, takt, economies of scale across the system, incentive systems, organisation design, problem exposure and resolution practices, as a whole.

Otherwise, flow as a remedy may fail due to losses in economies of scale (changeover losses, yield losses, transfer costs). Lacking teams who help each other out, a safe way to expose problems, a standard way of addressing root causes, creating incentives that align the team to improve as opposed to overproduce, build up stock and take it easy, flow fails to take hold. So an “an apple a day keeps the doctor away” has form, provided the main thing lacking in our health is one daily serving of fruits and vegetables.

The benefits of folk medicine also show instructive parallels to lean:

  • By and large, the practices and remedies that have survived are the ones that have worked, or at the very least do no harm;
  • Folk medicine and lean can be practiced by anyone, provided we do not make claims that are illegal or unfounded;
  • As with many fields, theory and science eventually catches up with practice in the field;
  • Folk medicine allows us to take on greater responsibility about our own health.

The last benefit is quite important. The practice of folk medicine gives people the sense of control over their own health. Simply by improving how we feel about being in control, by definition we are improving wellness. Studies show a promising relationship between the human immune and nervous systems, such that a reduction in stress contributes to improved health. By being able to do simple things, applying folk remedies in judicious combination with modern and proven medical science, people have a better chance of achieving and maintaining good health and wellness. There are strong parallels here to organisational performance and employee engagement. Studies have shown that when employees feel they have the means, the time and the permission to do their best work and be their best self, performance improves. The means to engage employees can be as simple as respecting them as part of the autonomous nervous system, enabling them to design their work to flow smoothly, and to provide a humane schedule and rhythm of work.

If lean is to become a science, certain scientifically-proven remedies must be prescribed based on scientifically proven diagnostic methods. Some of these remedies may be practice the scientific method and develop your people through problem solving. However, one would hope the best advice from modern medicine to someone who is ill would not be reduced to try various remedies and see which ones work and learn to detect your symptoms earlier. A responsible and unbiased practitioner of human or organisational medicine would not hesitate to prescribe a regimen of the best known tools, methods and systems to practice in specific, tested ways. A minimum standard prescription should be developing a clear understanding of the problem, conducting a thorough diagnosis, and an intervention that does no harm.

Robert Pirsig wrote in Zen and the Art of Motorcycle Maintenance (1974): “The real purpose of [the] scientific method is to make sure Nature hasn’t misled you into thinking you know something you actually don’t know.” We don’t know if lean is a science. We can barely agree on a definition of lean. Those of us who have made careers of lean, by nature, are biased towards strongly believing that lean is a genuinely helpful, scientifically valid, and valuable human endeavour. But the truth is we don’t know. Let us start applying the scientific method to the proposition of lean as a science.