# What is “Operational Excellence”?

Who would not want something called “Operational Excellence”? “Excellence” is superlative goodness, and “Operational” suggests a scope that includes not only production, logistics, and maintenance in Manufacturing, but also administrative transaction processing like issuing car rental contracts or marriage licenses. The boundaries are fuzzy, but Marketing and R&D are not usually considered part of Operations.

Hearing “Operational Excellence” for the first time, everybody takes it to mean whatever they think is the best way to run operations, which makes it unlikely that any two people will have the same perception. If marketers of consulting services can prevail upon a profession to accept such a vague and generic term as a brand, they can sell pretty much anything under this label. By contrast, the Toyota Production System (TPS) specifically refers to the principles, approaches, methods, and tools that Toyota uses to make cars. When you first hear it, you may not know what those are, but you know that you don’t know. Another difference between “Operational Excellence” — also known as “OpEx’ or “OE” — and TPS, is that the first is a goal, while the second one is a means to achieve the unmentioned but obvious goal of thriving in the car industry.

OE at Chevron

It is an increasingly popular term, perhaps because of its very lack of precision. Google it, and you find, for example, that, Chevron “has spent more than 20 years expanding systems that support a culture of safety and environmental stewardship that strives to achieve world-class performance and prevent all incidents. We call this Operational Excellence (OE),…”  So, at Chevron, OE is about avoiding accidents that directly hurt people and oil spills that ruin the environment.

It is certainly not what it means to the  Institute for Operational Excellence. Its website has a glossary that contains exclusively terms from TPS or Lean, like Andon, Cell, Chaku-Chaku, 5S, Kanban,…, which strongly suggests that Operational Excellence is just the latest avatar of TPS when applied outside of Toyota. For 25 years, “Lean” has reigned supreme in this role but may finally be getting stale after so many botched implementations.

The Utah State University website, on its Jon M. Huntsman School of Business page, has a directory entry for The Shingo Prize for Operational Excellence. The Shingo Prize site itself, however, while using “excellence” in almost every sentence, does not refer to operational excellence. The theme of this year’s Shingo Prize conference, in Sandusky, OH in May, was “Enterprise Excellence,” which sounds like a further generalization. But, digging deeper, you find that the Shingo Model Handbook contains “operational excellence” 31 times, “Lean” 7 times,  “Toyota”  twice, and “TPS” never.

Shigeo Shingo

Stuck gears on the Shingo Prize page

The Shingo Prize page uses as a banner a picture of three gears with the teeth enmeshed in such a way that they can’t move, a picture that would have seemed odd to an engineer like  Shigeo Shingo. His legacy is primarily contributions to production engineering like SMED, Poka-Yoke, and line/work station design. On these subjects, you cannot see daylight between Shingo’s work and the Toyota Production System (TPS). Therefore, when you see a document called “Shingo Model Handbook” that refers repeatedly to Operational Excellence and never to TPS, you can’t help but conclude that Operational Excellence is just another name for TPS.

UC Berkeley OE Program Office Team

UC Berkeley has an Operational Excellence (OE) Program Office. Based on the family picture in its Spring 2014 Progress Report, it has 12 members. UC Berkeley has a total workforce of 29,000, of which 2,000 are full and part-time faculty members, and about 36,000 students. It works out to 1 member of the OE Program Office for every 2,417 members of the work force and 3,000 students. They present themselves as  internal consultants, with access to funding and expertise in “project management, change management, strategic planning, campus engagement, financial analysis and planning, business and data analysis, and communications.” The director of the office has been on the administrative staff for 13 years and reports to the university’s chief administrative officer. This is yet another take on it.

Do the proponents of Operational Excellence do a better job of capturing the essence of TPS than their predecessors in Lean, World-Class Manufacturing,  Synchronous Manufacturing, or Agile Manufacturing? The above-mentioned institute has a page defining Operational Excellence as “the point at which ‘Each and every employee can see the flow of value to the customer, and fix that flow before it breaks down.’”

At first, it sounds like another version of True North, as explained by Art Smalley. Taking a closer look, as a general statement, it does not make much sense. It implies that every employee of every organization is involved in something that can, at least metaphorically, by described as a “flow of value” to customers. It is no stretch to see how this applies to a hot dog street vendor, but how does it work for, say, a firefighter? A firefighter serves the public by putting out fires, but the value of a firefighter resides in the ability to put out fires when they occur, not in the number of fires put out. A firefighter “seeing a flow of value to customers” is a head scratcher. As for “fixing the flow before it breaks down,” it conjures up the image of a plumber repairing a pipe that doesn’t leak.

Even Wikipedia editors are uncomfortable with their article on Operational Excellence. They denounce it as “promoting the subject in a subjective manner without imparting real information.” The definition is indeed short and confused:

Operational Excellence is an element of organizational leadership that stresses the application of a variety of principles, systems, and tools toward the sustainable improvement of key performance metrics.

Much of this management philosophy is based on earlier continuous improvement methodologies, such as Lean Manufacturing, Six Sigma, and Scientific Management. The focus of Operational Excellence goes beyond the traditional event-based model of improvement toward a long-term change in organizational culture.

It says what Operational Excellence is an element of, what it is based on, and what it goes beyond, but not what it is. And much of what these few words say raises eyebrows:

1. The emphasis on metrics is a throwback to Management-By-Objectives, an approach that has historically not led to excellence at anything but gaming metrics.
2. Lean Manufacturing, Six Sigma, and Scientific Management are emphatically not continuous improvement methodologies. Continuous improvement is a component of Lean but by no means all of it. Six Sigma is not continuous improvement at all, and Taylor’s “scientific” management was about preventing operators from colluding to curtail output, not improving processes.
3. Continuous improvement is not event-based.  Contrary to what the name suggests, “Kaizen events” don’t do continuous improvement. This format was actually developed in the AME in the 1990s based on the realization that just continuous improvement could not accomplish changes of the scope that was needed.
4. TPS/Lean, when correctly implemented, has always been about a long-term change in organizational culture.

# Absence of “Value Added” in the TPS literature

When improving operations, the only distinction of practical relevance is between necessary and unnecessary activities (See Occam’s Razor… and Whack-a-Mole). It really doesn’t matter whether they physically transform a product or whether a hypothetical customer would be willing to pay for them; the only thing that matters is whether they are needed to get the job done. Eliminating the unnecessary means getting the right things done, or being effective. The step after that is getting these things done right, or being efficient.

The American literature on Lean is centered on Value Added — defined as “what the customer is willing to pay for.” As I indicated, this is not the case for the Japanese literature or even the American literature on the Toyota Production System (TPS). I listed some examples from my personal library in Occam’s Razor…, and would like here to give more specifics.

## 1. “Value Added” in the TPS Literature

The following books on TPS — ranging in vintage from 1977 to 2009 — contain no reference that I could find to value added:

• Fundamental Principles of Lean Manufacturing, Shigeo Shingo (1977). The English title contains “Lean Manufacturing,” a term that wasn’t coined until a decade after this book came out. Shingo’s title translates to “Original intent of plant improvement” (工場改善の原点的志向).
• Zero Inventories, Robert W. Hall (1983). This was the first book in English to cover the technical content of TPS. ‘Doc’ Hall is an American academic, who researched Japanese sources. He is still active today in the AME, and was inducted in the Manufacturing Hall of Fame in 2012.
• Kanban, Just-In-Time at Toyota, JMA (トヨタの現場管理：カンバン方式の正しい進め方, 1985). This is based on training materials from one of the oldest manufacturing consulting firms in Japan.
• The Evolution of a Manufacturing System at Toyota, Takahiro Fujimoto (1999). Fujimoto is an academic who studied the emergence of TPS in the history of Toyota and, in the process, explains many details of its development in the 1990s.
• The heart of introducing TPS (トヨタ生産方式導入の奥義）Mikiharu Aoki (2009). The author left Toyota in 2004 after 26 years to become a consultant. He is still in his fifties, and what he describes is not your grandfather’s TPS. Still, there is not a word about value added.

There are mentions of value added in a few books on TPS, but they are brief and no connection is made with customers’ willingness to pay. In these books, what is called “value added” is what physically transforms the product, a definition that, incidentally, has its own problems. Following are the books I have on TPS that contain a fleeting mention of value added:

• Toyota Production System, Taiichi Ohno (トヨタ生産方式, 1978). “Value Added” is discussed on pp. 57-58, and that’s it: two pages out of a 132-page book. The English translation includes the following diagram, which does not quite match the Japanese original:

The original, Japanese diagram was as follows, with my  own annotations in red:

There are differences in both style and content:

• The “Value-added work” caption in the translation does not make sense in its context and does not match the original, which is just one word, “sagyo” (作業) which just means work or operation.
• The bullet lists in the translation do not match the starred captions in the original, which only contain the first two items. I don’t know why the translator added items to each list.
• The original figure is in the style of a comic strip, which is almost standard for the Japanese literature on manufacturing. It is not intended to impress readers of the Harvard Business Review, but to communicate with people who read manga while riding trains to work.

One vital feature of this discussion is that it is exclusively about the breakdown of operator movements. It is not about materials handlers, managers or any kind of support groups, whose work is branded as intrinsically “non-value added” by managers who have read the US Lean literature.

Why this narrow focus on production operators? Most organizations have a subgroup of members who fill its purpose while all others support them. In a hospital, it is the surgeons; in aviation, the pilots; in the military, the shooters; in car racing, the drivers. In a manufacturing company, it’s the production operators. And their time is particularly precious because they work in sequence, so that, if you delay any one of them, you delay the entire production line. This is not true of the support staff, who work mostly in parallel.

Even in the restricted sense that he uses, if Ohno had felt that this was an important concept for TPS, he certainly would have used it elsewhere in his book. But he didn’t.

• Toyota Production System, Yasuhiro Monden, 2nd Edition (1993). Monden is a professor of production management at Tsukuba University, who has been granted extensive access by Toyota. Value Added appears once, on p. 179 of this 423-page book, where he repeats what Ohno had written.
• 25 keywords of the Nissan Production Way (実践日産生産方式ｷｰﾜｰﾄ25, 2005). This book is about Nissan, not Toyota. Keywords 11-15, on pp. 62-83 are about “the pursuit of Value Added production” (付加価値生産)。 “Value-added tasks,” however, are simply defined as the ones that physically modify the product.
• The Birth of Lean, Koichi Shimokawa and Takahiro Fujimoto (Ed.) (2009). There is one instance of “value added” on p. 52.
• The Toyota Way, Jeffrey Liker (2003). On p. 27, it says “The first question in TPS is always ‘What does the customer want from this process?’ (Both the internal customer at the next steps in the production line and the final, external customer.) This defines value. Through the customer’s eyes, you can observe a process and separate the value-added steps from the non-value-added steps.”
• Since “internal customers” are really downstream operations that don’t pay, the willingness-to-pay criterion is not applicable, which explains why Liker changes it to what the customer “wants from the process,” and it may not be a physical transformation. For example, what car assembly wants from painting inspection is the assurance that the bodies started on the final assembly line are free of paint defects.

Later, on p. 89, the concept migrates to an engineering office. Finally, on p. 280, value-added work is “the actual transformation process core to the service that the customer is paying for.” So the willingness to pay that was excluded on p. 27 is back in, and so is the physical transformation, apparently mashing together the US Lean and Japanese TPS versions of value added. Again, this concept is only referenced in three of the book’s 330 pages, which strongly suggests that it is not important. Toyota is just not that into it.

## 2. Value Added in Lean

In light of this, why have American Lean authors focused on value-added? They zoomed in on a minor detail, changed the meaning from physical transformation to willingness to pay, and made it the foundation of Lean.

My personal guess is that they felt it necessary to attract decision makers under the influence of business schools and  uncomfortable with TPS plain talk. If we need to intellectualize the notion of waste elimination, however, we can do it in other ways, for example by stating as principle that a factory in never Pareto-optimal, meaning that it can always be improved.

In fact, it is fortunate that the concept of value added plays such a negligible role in TPS, because, as discussed in More Musings on Muda,  its definition in terms of physical transformation doesn’t withstand scrutiny much better than that in terms of willingness to pay. In particular, it is not applicable to anyone who does useful work that does not physically change a product.

In addition, in both senses, “value-added” is an attribute that an activities possesses or lacks. In economics or game theory, value added is a quantity of money.

In economics, the value added of a business is the difference between sales and external inputs, where the external inputs are materials, energy, and outsourced services. In other words:

$Value\: Added = Sales - \left ( Materials + Energy + Outsourced\: Services \right )$

This is the basis for Value-Added Taxes (VAT) in countries that charge them and. Aggregate it over an entire country, and you get its Gross Domestic Product (GDP).

Out of this Value Added, companies have to pay for people, facilities and equipment, and taxes. I have found this concept useful in several contexts. For example, a plant’s value added per employee is a better measure of productivity than sales per employee, because you can’t game it by outsourcing.

I have also found it useful to compare a company’s value added per employee with industry averages that you can retrieve from sources like the US Bureau of Labor Statistics or the Economic Census. But it is clearly not applicable to one production operator at one work station.

In game theory, the value added of a player is the amount by which his presence increases the size of the pot. A player who joins a poker table puts more chips in play. A company that sells software to run on a given hardware platform increases the value of this platform, while a competitor providing alternative hardware to run the same software reduces it. As explained in Brandenburger and Nalebuff’s Co-opetition, it is a useful concept in business strategy, but also irrelevant at the level of an individual work station.

Yet another use of the term is found in corporate finance, where the Economic Value Added (EVA)  is the difference between a company’s net, after-tax profits and its cost of capital.  The idea is that, unless a company has a positive EVA, its investors would be better off putting their money elsewhere.

None of these uses is applicable to a work station on the shop floor of a manufacturing plant, and there is no way any of them is connected to the notion of willingness to pay.

Focusing on what customers are willing to pay for is a direction that might be given to Marketing. Top management must of course be concerned with customers, but also with suppliers, employees, the local community, the environment,  local and national governments, not to mention creditors and investors.

Because TPS is a system that was developed by an actual company with all these stakeholders and more, it encompasses approaches to supply chain management, human resources, corporate social responsibility, and finance. In this context,  the notion that only activities add value only if customers are willing to pay for them is not helpful and is inconsistent with the more general usage of “value added”  as a technical term.

# Lean implementers: don’t forget engineering!

Just about everybody says that the involvement and personal engagement of top management is the main challenge in Lean implementation. “Key to the success of lean manufacturing,” said the keynote speaker at an industry association meeting in Santa Clara, CA, “is that the leadership team needs to fully buy into the method and remove workplace obstacles so that employees can achieve results.” While he didn’t say it, I am sure his audience heard that management doing as he says is all it takes to implement Lean successfully.

In an informal survey taken recently by blogger Vivek Naik among his readers, no one mentioned insufficient mastery of the engineering and management tools of Lean as a cause of failure. The existence of tools is generally recognized, but most consultants and implementers take them for granted. They are assumed to be simple, widely known and not new. Some, like Bill Kluck, even call the tools “trick shots.”

When you read that the details of Lean tools are widely known, you wonder where and by whom. How many manufacturing managers or engineers do you know who understand heijunka, cell design, work-combination charts, SMED,  the proper use of andons, mistake-proofing, or jidoka? Considering that these tools are the results of 75 years of development at Toyota, and that most of the Japanese literature on Lean is about technical content, I find this dismissal cavalier, to say the least.

It does not happen in other human endeavors, like building a world class soccer team.  Top management commitment is obviously required, but no one would claim that it is sufficient. You don’t hear of dribbling, passing, shooting, receiving or throw-ins as low-level skills that everybody has anyway and that you don’t need to focus on. Soccer teams actually train relentlessly to develop and maintain these skills, and everybody involved, even the fans, fully realize their importance and admire the star players for their mastery.

To understand the issues, and remedy this situation, I would like to dive deeper into the following topics:

## 1. The engineering dimension of Lean, and the other dimensions

So why is it different in the competitive game of manufacturing? For one, it is more complex than soccer, and few people have a holistic view of it. One who does is my colleague Crispin Vincenti-Brown, and he has identified four dimensions to this game, and you must pay attention to all if you want to win. They are as follows:

1. The engineering of production lines.
2. Logistics and production control.
3. Organization and people.
4. Metrics and accountability.

In the US, the Lean movement has ignored the engineering dimension. Logistics receives some attention, but Lean programs are overwhelmingly focused on the last two: organization and people issues, and metrics. It is out of balance, and I believe this is a key reason for Lean programs to fail.

Lean implementers, whether employees or consultants, come from a variety of backgrounds. In the US, few are engineers. You see MBAs, psychologists, marketing people, and the occasional cognitive sociologist and defrocked priest. There is nothing wrong with having all these different perspectives, as long as they don’t blind you to the whole picture. The psychologist takes engineering for granted while the engineer does the same for people issues and the production control manager thinks that everything revolves around planning and scheduling….

On the one hand, you cannot have a successful implementation unless you address all these dimensions in the right sequence. On the other hand, you cannot expect any individual to master all of them, but you need a team that does, in which every member understands that his or her perspective is not the whole picture, and leadership that can pull all the strings into a coherent approach.

## 2. What is special about engineering on a factory floor?

This still does not explain why it is Engineering of production lines that is given short shrift, even in a country like the US, that has contributed so much to this field, and that still has a vibrant engineering community in other technical specialties. What is it about the engineering of production that sets it apart?

The heat of the forge, the sparks from welding, or the din of the assembly line, and interactions with the people who work in these environments,… are not for everybody. Most universities do not know how to teach this kind of engineering. Its subject matter straddles what they call Industrial Engineering and Manufacturing Engineering.

Industrial Engineering (IE), as taught in American universities, is generically about how people work, and gives you no process-specific knowledge. Manufacturing Engineering (ME), on the other hand, is heavily focused on metal working operations, as if these were the only processes worthy of the name “manufacturing.” In principle, you should be able to become a Manufacturing Engineer specialized in all sorts of other fabrication or assembly processes, but the label is in fact used only in metal working.

We could expect, however, those who pursue degrees in IE or ME  to be comfortable on a production shop floor, but most aren’t. Some years ago, my colleague Hormoz Mogarei and I gave a seminar to PhD candidates in Industrial Engineering at Stanford University. We wanted to tell them what we did to get them interested in working with us. Their response, however, was that it was beneath them, and that they had not gone this far in school to do such low-level work.

For factory work, Shigeo Shingo had identified two types of engineers to avoid: the catalog engineer, whose solution to every problem is buying new equipment, and the “no” engineer, who always has a reason why it can’t be done, has been tried before, or won’t work. One more category that did not exist in Shingo’s day but does today is the PowerPoint engineer, whose focus is animating slides.

Historically, with the exception of Lillian Gilbreth who had a PhD, the key innovators in this field, from Frederick Taylor, Frank Gilbreth and Alexei Gastev to Taiichi Ohno and Shigeo Shingo were all self-taught and had no advanced degrees. To this day, the engineers who are most comfortable and effective on a production shop floor started working there as operators in their youth and later went back to school or  learned  through continuing education or apprenticeship programs that alternate extended internships with classroom training. These engineers combine the requisite technical knowledge with an understanding of the operator experience and the ability to work with operators on improvements.

## 3. Engineers in Lean implementation

And having practical, shop-floor minded engineers in your plant is still not sufficient. You also need to use them effectively. In manufacturing, if you provide an “engineering sandbox,” organize for people to tinker in it, and provide some form of recognition, you will get results. The engineering sandbox is a space set aside and outfitted with the resources needed for tinkering, experimentation, and prototyping. It is used both by individuals and teams.

Engineering Sandbox

In Wikipedia, the space you can use to draft an article or an edit before publishing it is called your “sandbox,” and it is similar in concept to the engineering sandboxes you find in factories, that are often called “Kaizen areas” even though the experimentation that takes place can exceed the scope of what is commonly designated as Kaizen. This space is best located in a secluded area, away from heavy traffic and prying eyes and, as it is shared by multiple individuals and teams, access to it must be managed accordingly and often takes place outside of regular working hours. Chihiro Nakao calls this activity “moonshine.”

The implementation of Lean involves engineering projects at multiple scales, from continuous improvement to new plant design. Which no engineering group can be large enough to execute on its own. While many companies set up a “Lean Engineering” group and task it with transforming the entire plant, it cannot work. The engineering group does not have the bandwidth to do no matter how hard its members apply themselves and, even if they did, the production organization would not own their output and would reject it.

The only way it can practically be done is by the production organization, under the leadership of its management at the appropriate level, with the engineers in a supporting role. The concepts emanate from the production organization. The engineers help with calculations, research available resources, generate technical drawings, and coordinate the use of contractors if needed. And they apply the lessons learned through improvement to new plant and new line designs where they play a central role.

Retrofit to a multicavity injection molding machine

At the start of setup time reduction projects, the focus is on organizing to prepare better before stopping the machine, which achieves initial results, mostly through the work of production operators. But to reduce setup times from 1 hour to less than 10 minutes, you need to go further and modify the machine, which requires engineering. And it’s not all about hardware. More and more machines are computer-controlled, and also require changes to their process programs. The picture to the left shows a device conceived and built by plant engineers, and retrofitted to an injection molding machine to separate the parts by cavity and better trace quality problems.

## 4. Correcting the imbalance in the US Lean movement

I am not the only one who has been working to lack of attention to engineering in the US Lean movement. J.T. Black, a professor of IE at Auburn University in Alabama, now in his seventies, was possibly the first American academic to recognize the significance of Lean and make it central to his teachings. Art Smalley, a consultant who is a Toyota alumnus, has also been vocal. But it is an uphill battle. Two of my books, Lean Assembly and Working with Machines, are on this subject, and both are outsold by Lean Logistics, which isn’t.

# Lean is from Toyota, not Ford, and not 15th-century Venice boat builders

Anywhere but possibly inside Japan, finding local roots for Lean is useful to defuse nationalism when implementing it, but it is also risky. You start by giving a local pioneer credit  for what he actually did. Similarity of his insights with Lean then becomes enough to label him a “precursor.”  It may be a stretch, but it is a white lie, and it makes local engineers and managers so much more receptive! Further down this slippery slope, however, the local precursor becomes a “pioneer” and soon there is nothing to Lean beyond what he came up with, at which point his legacy impedes Lean  implementation more than it supports it. This is where Lean is attributed to Henry Ford.

In reality, while the founders of Toyota learned everything they could from foreign sources in early days, they and their successors are the ones who put the Toyota Production System (TPS) together and made it work, before the term “Lean Manufacturing” was coined. A Toyota alumnus told me that he never heard Toyota people claim they had invented anything; after all, they are in the car business, not the production system business. What is unique about their work is that they have integrated all the pieces — borrowed or not — into a system that outperformed the competition. As part of its 75th anniversary celebration, Toyota published the following illustration of its overall system:

From the Toyota 75th anniversary web site

They also published a detailed timeline of the development of TPS  from 1945 to 2005, highlighting the key challenges the company faced in each period, and the solutions it adopted in Just-In-Time and Jidoka. Each item has a short explanation in text, and is illustrated with cartoons, technical drawings, and photographs. It is an excellent and balanced account of the technical content of TPS, and I recommend going through it to understand how the pieces fit together.

Based on this timeline, other details contained in the 75th anniversary website, and a few other sources, I compiled the following summary, going back further in time, and emphasizing international exchanges. What I find most striking about this timeline is that the foreign inputs to TPS, primarily from the US and secondarily from Germany, were over by the mid 1950s, almost 60 years ago, and that, since the late 1970s, the flow is in the opposite direction, with the rest of world learning from Toyota.

TPS is still a work in progress. It has been and still is primarily an original development. The bulk of TPS has come from the minds of inventor Sakichi Toyoda, his son Kiichiro, engineers Taiichi Ohno and Shigeo Shingo, and hundreds of thousands of Toyota employees over decades. A trade secret until Toyota started training suppliers in the 1970s, TPS was revealed to the world with the publication of Taiichi Ohno’s book in 1978.

The American influence, particularly Ford’s, is readily acknowledged and played up in Toyota’s official literature. The German contribution, while not hidden, is in small print. Takt  is a central concept in TPS, and it came to Toyota from the Mitsubishi Aircraft plant in Nagoya, which had learned it from German aircraft manufacturer Junkers. After the subject of Takt came up in a LinkedIn forum a few months ago, I pulled on this linguistic thread to see what came out, and I was surprised by the magnitude of it, essentially a whole production system for aircraft, including some principles of supply chain management. It is summarized in the following blog posts:

Toyota’s study of automotive technology also included reverse engineering a 1936 DKW from Germany, and Toyota’s first postwar model, the 1947 SA, looked like a Volkswagen beetle.

Why Toyota designers chose to imitate this particular car at that particular time is another mystery, but not relevant to the key point here, which is that all of this borrowing from abroad is ancient history.

By Michel Baudin Posted in History

# Shigeo Shingo’s first name misspelled twice in article on mistake-proofing

See on Scoop.itlean manufacturing

“The causes of defects lie in worker errors, and defects are the results of neglecting those errors. It follows that mistakes will not turn into defects if worker errors are discovered and eliminated beforehand.” — Shiego Shingo, 1986

Sheiego Shingo, the Japanese industrial engineer credited as one of the world’s leading experts on manufacturing practices and the Toyota Production System, termed pre-mistake discovery and elimination as poka-yoke, which translates to “fool proofing” or more recently “mistake proofing.”

Michel Baudin‘s insight:

And it is misspelled in two different ways!