A Brief History of Kaizen: The Key Players

A Brief History of Kaizen: The Key Players

Walter A. Shewhart

Walter A. Shewhart was an American statistician, physicist and Engineer. In the 1920s, while he worked at Bell Laboratories, Shewhart created the concepts of the statistical control of processes and Shewhart also developed the control chart tool.

Statistical Process Control

Statistical Process Control, or SPC, is the method developed by Shewhart in 1924. It exists to monitor or regulate a process to guarantee it functions to its highest capabilities.

SPC is a method of quality control using statistics. If the process remains the same the outcome will remain the same; you can predict what will happen in the future based on what has happened in the past. Through his SPC concepts, Shewhart revealed that having a production process in a state of statistical control and keeping it in statistical control was imperative to have the ability to predict the future output from a specific production process.

In SPC, instead of correcting issues after they occur, there is an emphasis on early discovery and avoidance of issues. This method makes it less probable that a completed product will have to be modified.

Main Phases of Activity in Statistical Process Control:

  • Comprehend a process
  • Understand the specification limits of the process
  • Make the process stable by removing assignable, unusual causes of variation.
  • Detect significant changes of mean or variation by monitoring the continuous production process. Use control charts as a tool to monitor a process.

To implement statistical process control, Shewhart combines the concept of a state of statistical control with the use of control charts.

Control Charts

Developed in 1924, Shewhart's control chart was also known as Shewhart's Charts, process behavior charts, and control charts. Control charts are tools used in statistical process control. These charts are used to conclude whether or not a business process or a manufacturing process is currently in a state of statistical control.

When a control chart shows that a process is stable or under control (where the only variations are established by variations that are common to the process) no changes are needed for the process. The chart can now be used to forecast the future output of this process.

When a control chart shows that a process is unstable or not in control the chart must be analyzed to see where the uncommon variation is coming from. It is important to figure out where the issue is coming from so that the output of the process is not hindered.

Here are some of the items that are found on a control chart:

  • Statistical points that represent measurements of a process' quality characteristics. These statistical measurements of quality are retrieved from the output of a process at different times so they can be used for comparison.
  • The mean of all of these statistical measurements of quality.
  • The mean of the statistical measurements of quality is notated by a centerline drawn at this number on the control chart.
  • The standard error or deviation is calculated based on all of the statistical measurements of quality that were collected.
  • The chart is marked with lower control limits and upper control limits to specify the number where the process production is unlikely (statistically speaking).

William Edwards Deming

W. Edwards Deming was an American who lived from October 14, 1900, to December 20, 1993. Deming was a management consultant, statistician, engineer, author, lecturer, and professor.

In 1927, Deming met Walter A. Shewhart. Deming was impressed with Shewhart's concepts of statistical process control. Deming studied Shewhart's work on statistical control, control charts, and Shewhart's straight-line process. Shewhart's concept of common causes of variation (known, historic, having to do with the process, and quantifiable) and special causes of variation (statistical variations that are unknown/haven't happened before, abnormal, and unquantifiable) directly led to Deming's theory of management. Deming recognized that Shewhart's concepts and processes could be applied to both manufacturing processes and the processes that manage companies.

Deming edited a four part series of lectures that Shewhart gave in 1937. These lectures were published in a 1939 book called, Statistical Method from the Viewpoint of Quality Control.

In the 1930s in the US, Deming worked with the US Census Bureau to help develop the sampling techniques they used in 1940 and still today.

In 1943, Deming educated engineers and additional people (in support of war efforts) in his first course on fundamental applied statistics. Then Deming began a two-year teaching program, teaching the statistics training program at Stanford. Deming.org says that here he educated close to 2000 people on the PDSA Cycle and the Shewhart Cycle for Learning and Improvement.

In 1946, Deming was working as a private consultant. After World War II, the Economic and Scientific Section of the War Department sent Deming to Japan so he could study agricultural production problems and other connected issues occurring in the nation, damaged by the war.

In 1947, Deming went to Japan to help the statisticians of Japan evaluate nutrition issues and housing troubles and to help in the early planning of Japan's 1951 census. While there, the Japanese Statistical Society (JSS) deemed him an honorary member.

In 1950, the Japanese Union of Scientists and Engineers (JUSE) studied Shewhart's cycle and wanted an expert to teach them more on the subject. JUSE members thus sought out Deming to teach them about statistical control.

Deming went on, in 1950, to teach people about concepts of quality and statistical process control (SPC). In Japan, Deming taught hundreds of top management industrialists, scholars, engineers, and managers. Deming's main teaching to executives was that increased quality decreases expenditures and increases productivity and market share. Multiple manufacturers in Japan followed Deming's techniques to achieve new levels of productivity and quality. A new international demand for products coming from Japan arose due to their decreased cost and increased quality. In the 1950s, from the processes based on what Deming taught, Japan was on the path to becoming the second-largest economy in the world. Deming can be credited for bringing the idea of continuous improvement to Japan.

In 1960, The Emperor of Japan gave an award to Deming for pioneering, introducing, and implementing Kaizen in Japan. The award was called the "2nd Order Medal of the Sacred Treasure."

Training Within Industry (TWI)

From 1940 through 1945, Training Within Industry was a program that was run within a United States government agency, the War Manpower Commission. This program was in place as an emergency service in the US during World War II. The United States Government War Production Board created TWI.

From the industry, experts were drafted to develop techniques to rapidly speed up war materials production. The program was needed to quickly train new unskilled workers in the war production workforce. These new workers were needed to replace the skilled workforce (that were producing war materials) that was now heading off to war.

The TWI programs consisted of basic training sessions. They were split up into 4 programs that were each 10 hours long.

The TWI program was developed from Charles R. Allen's 4 step method of training new workers: Show, Tell, Do, Check. Charles R. Allen was a Massachusetts vocational teacher. In 1917, during World War I, Charles was appointed to head a program to increase trained workers for the ship building industry 10-fold. In 1919, he published his work in his book titled, "The Instructor, The Man and The Job."

The 4 TWI training programs were:

  • Job Instruction (JI): This was a course to teach experienced workers, managers, and supervisors to quickly train untrained employees. Trainers were shown to take jobs and separate them into small-defined steps, to demonstrate the steps while explaining the key steps and the reason for them, and then to closely watch the student demonstrate the procedure, coach them, and slowly end coaching as the student can do it without the trainer.
  • Job Methods (JM): This was course to teach workers to meticulously evaluate (objectively) the efficiency of the job and to suggest logical improvements. If the worker came up with a inefficient task, they were charged with the task of coming up with a solution by getting rid of something, combining steps, rearranging, or simplifying steps. The worker must then present the idea to coworkers and their supervisor and try to gain approval.
  • Job Relations (JR): This was a course to teach managers/supervisors to handle employees both effectively and in a fair manner.
  • Program Development (PD): This was a session to teach trainers to help in the organization of solving issues with production through training.

After WWII, the Economic and Scientific Section (ESS) group was assigned to helping improve management skills in Japan. Part of their work was to properly teach the Training Within Industry programs, in Japan. To aid in their work, ESS introduced a TWI training film. This TWI training film taught Job Instruction (JI), Job Methods (JM), and Job Relations (JR).

The TWI training film was called "Improvement in 4 Steps." In Japanese, this translates to Kaizen eno Yon Dankai. Some see this as the formal introduction of Kaizen into Japan.

The TWI training was widely accepted in Japan as it and Deming's teachings developed into the foundation of the Kaizen culture in Japanese industry.

Toyota Motor Corporation

The Toyota Motor Corporation was one of the Japanese companies who harnessed the knowledge of Kaizen, the teachings of Deming and the TWI program.

In 1950, Toyota established using quality circles. Deming first described quality circles earlier that year. They are also known as quality control circles. A quality circle can be defined as groups of employees with the same job or a similar job who get together consistently to define, analyze, and offer solutions to issues related to their work. A manager normally heads the meeting. This manager will then bring the solutions of the group to higher management.

The use of quality circles and the TWI training programs helped lead to the development of the Toyota Production System (TPS).

The Toyota Production System is based on the philosophy of the total eradication of all waste, or "muda." The system utilizes Kaizen, Just-In-Time, and Jidoka.

Today, Toyota still uses TPS and dedicates time and energy to sharing the system with other industries. In the Toyota Production System Support Center there is more information on the ways Toyota supports the community.

Masaaki Imai

The idea of continuous improvement and Kaizen were first brought to Japan after World War II. These ideas then returned to the West in the late 20th century through the publications and work of Masaaki Imai, Norman Bodek, and others who worked with or studied Lean and the Toyota Production System.

Imai was born in 1930 in Tokyo, Japan. He is a management consultant and author. He is known for working on Kaizen and quality management.

Masaaki Imai's 1986 book Kaizen: The Key to Japan's Competitive Success was the first to introduce the idea of kaizen to the business communities of Europe and North America. The text was translated from Japanese into more than a dozen languages, and kaizen made its way around the globe.

In 1985, Imai founded the Kaizen Institute to promote Kaizen worldwide.

Today, Imai is still chairman at the Kaizen Institute.


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