The Quality Gurus and pioneers that led to Six Sigma

Dr. Genichi Taguchi (1924-2012)

Taguchi met Walter Shewhart when he was a visiting professor at the Indian Statistical Institute. Awarded the Deming Application prize in 1960. Associated with the “signal-to-noise” ratio.

Known for:

Taguchi Methods - Quality and reliability built into the design stage, more important than process quality control.

Taguchi Loss (aka Quality Loss Function) - traditional decision on good or bad depends whether or not it is within the specification range (between the LSL and USL). With this approach, the specification range is more important than the nominal (target) value. He pushed further to make the product as good as possible even if it is within specification.

Taguchi specified three situations:

Larger the better (such as the process yield);
Smaller the better (such as injury rate, emissions, rejection rate)
On-target, minimum-variation (such as part dimensions)

Design of Experiments (DOE ) – structured study of the factors that the team has determined are the key process input variables (KPIV's) that are the source of the variation or have an influence on the mean of the output.

Robust Design – 3 stages to develop process/products that are not impacted by parameters outside the control of the designed/develop. 1) System design stage 2) Parameter Stage 3) Tolerance design stage.

Taiichi Ohno (1912-1990)

Ohno worked at Toyoda Spinning and Weaving Works in 1932 which later became Toyota.

Known for:

Toyota Production System (TPS) – later evolved into Lean Manufacturing which included his next credit… Seven Wastes. TPS accelerated Toyota to become world-class producer starting in the 1970’s and even today others are striving to duplicate their success.

Seven Wastes (Muda) – DOTWIMP is an acronym for Defects, Overproduction, Transportation, Waiting, Inventory, Motion, Waiting, Overproduction, Processing (Excess) and Defects).

An 8th waste was later added referring to the underutilization of human assets, talent, and skills.

Philip B. Crosby (1926-2001)

Crosby was an American businessman that first introduced the concept of Zero Defects. Most often identified with creating a core of quality specialists within an organization. Another strong advocate for upper-level management involvement.

Also known for:

14 Points of Quality

4 Absolutes of Quality – Doing It Right the First Time (DIRFT).

Definition of “Quality” is conformance to requirements (requirements meaning both the product and the customer's requirements)
The system of quality is prevention
The performance standard is zero defects (relative to requirements)
The measurement of quality is the price of nonconformance

Dr. Kauru Ishikawa (1915-1989)

Ishikawa is most notably credited with the Fishbone Diagram (aka Ishikawa Diagram and the Cause-Effect Diagram).

Also known for:

Seven Basic Quality Tools - applying the following tools to Quality Circles to get to the root cause and develop solutions: Check Sheet, Flow Chart, Control Chart, Fishbone Diagram, Scatter Diagram, Pareto Chart, Histogram.

Quality Circles - small group of employees in the same line of work that would apply the tools above. They meet in regular intervals to identify root causes and solutions. This became an important component of Total Quality Management (TQM).

He expanded the management concepts of Deming and Juran into the Japanese system with an emphasis on company-wide quality control. Pushed the mindset that the next operation was to be treated as a “customer”.

Dr. Armand V. Feigenbaum (1920-2014)

Feigenbaum was educated at MIT and became an American expert on quality control. Published book called Total Quality Control which later evolved into the underlying concepts of Total Quality Management (TQM).

Known for:

Total Quality Control – a system for integrating the quality development, quality maintenance, and quality improvement efforts of the various groups in an organization so as to enable production and service at the most economical levels which allow full customer satisfaction.

Quality Costs (aka Costs of Quality) – four categories of costs related to keeping Control (prevention and control) and making conforming products plus the costs of Non-Conformances (internal failure and external failure).

Hidden Plant (Factory) – belief that a high % of capacity is lost due to lack of first-time quality. There are a lot of costs that aren’t visibly clear on the surface (the iceberg concept) and a significant amount of costs are hidden.

Accountability for quality: “Because quality is everybody's job, it may become nobody's job—the idea that quality must be actively managed and have visibility at the highest levels of management.”

Shigeo Shingo (1909-1990)

Known for:

Poka-yoke - is a Japanese term corresponding to “mistake-proofing”. He broke down the types of poke-yokes into three types and the term became part of the Toyota Production System.

Single Minute Exchange of Dies (SMED) a Lean manufacturing concept that involves a relentless pursuit to reduce the amount of time to set up a process. The goal is to reduce this non-value added time and then reduce the lot size during each run, thereby reducing the amount of in process inventory.

Just-in-Time (JIT) - aka “synchronous flow”. A production method that strives to create a flow of all the necessary inputs for the process in the right amount at the right time. The objective is to optimize inventory levels with the intention of reducing excess inventory and carrying costs (remember that not all inventory is bad).

Other notes

Juran, Deming, and Crosby all believed that management is ultimately responsible for quality.

Juran and Dr. Frank Gryna are credited with developing the Optimum Quality Cost Model that shows that as Prevention and Appraisal costs increase, the costs of Failures decrease until a optimal value is achieved.

Noriaki Kano developed a model (Kano Model) for customer satisfaction that classifies customer preferences among five categories.

Carl Frederick Gauss (1777-1855) introduced the concept of the normal curve.

Douglas McGregor began teaching his theories to students at MIT in the 1950’s. He introduced theories called Theory X and Theory Y and also expanded on Maslow’s hierarchy of human needs.

Elton Mayo studied the effects of worker output and fatigue as part of the Hawthorne studies in 1924. Although a primary goal was to study the effect of illumination of worker output, a key find was that people reacted positively to increase productivity as long as their individual needs were met and they were treated as human beings. The Hawthorne Effect indicates that people that are singled out for special attention tend to perform as anticipated.

Frederick Herzburg studied the motivation to work and divided into two factors (the names of these factors vary).

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