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Variations


Fredrick Taylor and Taiichi Ohno. Two giants in the field of operations management. I want to compare these two thinking on one topic, “Variation.”

Why am I bringing this topic? Today, there are new words like “internet of things,” “industry 4.0,” etc. But what are these “new” technologies trying to do? Without understanding the variation, we might be using the technology for the wrong thing.


1. Taylor & Ohno started with the same message, “Use the best time for standard.”

2. The difference in approach on “Variations.”

3. Why is this topic important today?




1. Taylor & Ohno started with the same message, “Use the best time for standard.”


As I read F. Taylor’s “The principles of scientific management,” I encountered many exciting points (and some not so impressive points). One of them was the following part when he was talking about time study.

“This one new method, involving that series of motions which can be made quickest and best, is then substituted in place of the ten or fifteen inferior series which were formerly in use. This best method becomes standard, and remains standard, to be taught first to the teachers (or functional foremen) and by them to every workman in the establishment until it is superseded by a quicker and better series of movements.”

Taylor, Frederick Winslow. The Principles of Scientific Management (p.53).


Taiichi Ohno stated as following in his book, “Workplace management.”

CHAPTER 38 The Standard Time Should Be the Shortest Time

Speaking of standards, time study is another thing everyone gets wrong. For example, people measure ten repetitions of a task and use the average value. I think this is the worst thing you could do. If you are watching a person doing something ten times, and if they are doing it differently each time, you should immediately correct them. Instead, people think, “That’s not my concern. I just learned the symbols and how to use a stopwatch and I write things down. And after measuring ten repetitions, the standard time will be set as the average of the ten times.” If you are going to take ten such unreliable measurements, you should choose the shortest time. Some say that is harsh, but what is harsh about this? The shortest time is the easiest method. Even if the ten repetitions are performed in ten similar ways, they are doing different things. The shortest time out of these is the easiest time. Therefore, you need to analyze why the others took several extra minutes or several extra seconds. Some say, “You can’t always do the work the same way,” but the times are different because something is wrong.


Ohno, Taiichi. Taiichi Ohnos Workplace Management: Special 100th Birthday Edition (p.145).


Both gentlemen are stating the same thing, use the best time as the standard. Yet, we have different impressions of these two thinking. And I think that difference comes from the “Variations.”


2. The difference in approach on “Variations.”


Variations, sometimes, we use the word fluctuations. Whichever the word, when we use the best time as the standard, we face this dilemma of variations in the actual cycle time of works.


Inside Taylor’s book, it is unclear how to approach this variation. Each functional teacher should teach the operators to master the skills. Even if an operator masters a skill, variations will happen. What to do? My hypothesis on why people resisted Taylorism comes from this unclearness of the approach against variations.

Taylor’s followers or critics did consider this variation. They developed methods like average time or providing allowances, which I call as post-Taylor approaches. As such methodologies prosper, Ohno’s critics come into place. What is the average time? Average skill or labor, does such a thing exist? How many samples to collect? Allowance? Why are we asking people to waste their time? In the end, trying to define something other than the best becomes biased information.

Ohno and Toyota did not ignore the problem of variation. They installed andon, or the help-chain so that people will call for help every time there is a variation. Once the variation is supported, they develop ideas to eliminate it. They implement one-by-one production not just because of flexibility but also to eliminate process variations. They don’t deliver components in large containers with variations in pick points. They conduct all kinds of maintenances to avoid variations in machine performances. The word, Mura, is listed with Muri (Impossible work; No science or logic) and Muda (Waste) as things to eliminate from the shop floor. A significant focus of Kaizen is targeting to eliminate Mura (Variation).


3. Why is this topic important today?

Today, our “technologies” have advanced, but what are they doing?

The other day, I was asked to standardize a process. The process measures a component and then selects the incoming materials to attach. Unfortunately, the incoming materials vary, and the operators had to repeat the measurements and adjust. I had opportunities to visit the upper stream of the incoming materials, where I found so many violations of the control plan. The poor upper stream management of the process caused the variation in materials. In the meantime, the engineers submitted to buy the latest technology to measure and adjust the materials.

These lessons about the variations are found everywhere.

a. How often do you see a functional person blaming the people and pushing to do more “training” when there is a problem? Did they go and see the cause of variation? Are they repeating the message made by Taylor?

b. How often do we hear that variations are unavoidable and see people rushing to implement allowances and/or stocks? Isn’t this the same mistake that Ohno criticized against those from the post-Taylor era?

c. I have heard that some criticized the help chain as being “naïve.” Or some claim that it is too expensive. The help chain is not naïve or costly. It is a necessity based on the nature of the process. Without such a help chain is repeating the same mistake of forcing the people to deal with variations.


There are many “new” terminologies appearing in operations management. “Internet of things,” “Industry 4.0,” etc. The question I have about these “new” technologies is that are we trying to deal with the “old” problem of variation? The majority of the philosophy behind these technologies is to calculate or adjust according to the variations. By the time a variation has happened, it has already cost the operations. The “new” technology will help us deal with the problem. Don’t get me wrong. I’m not saying we don’t implement these technologies. Please don’t use these technologies to deal with variation. Instead, use them to prevent.

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