Several key pioneers played pivotal roles in developing the quality theory upon which Six Sigma is based. Let see who they are and what they say about Quality…
American Quality Gurus
Dr. Walter Shewhart
“Quality is controlling variability.”- Shewart
Dr. Shewhart described the role of process variation in reducing errors in the process, which is also the deviation from the mean, or sigma. //
The idea of reducing variation through the application of statistical methods was the basis for the Statistical Process Control method (SPC) – another fundamental quality theory underlying Six Sigma.
Dr. Shewhart was the first to use control charts to indicate where variation occurs in a process, and when to act on it. Control charts are used in a similar way today, and form the basis of SPC. He also made noteworthy contributions to the development of the PDCA (plan-do-check-act) cycle, together with one of his pupils, Dr. Deming.
Dr. W. Edwards Deming
“Quality is predictability” – Deming
Dr. Deming’s theories focus on system improvement. Most notable of his contributions is his support of the PDCA (plan-do-check-act) cycle as a method of system improvement.
Statistical Quality Control (SQC) concepts were first adopted at Bell Labs, where Dr. Shewhart and Dr. Deming were members of the Bell Labs’s Teams. Focus of their work was identifying and eliminating the cause of defects.
“Quality is conformance to customer requirements” – Crosby
Philip Crosby is well known for making seemingly complicated statistical methods easily understood and accessible to ordinary managers. //
Crosby is well known for saying that the cost of quality must be separated from other financial costs and for saying that measuring quality is vital to its maintenance.
He also outlined the four absolutes of quality management:
- quality means conformance to requirements
- quality comes from error prevention
- the quality performance standard must be zero defects
- quality should be measured in terms of the price of nonconformance
Dr. Joseph Juran
“Quality is fitness for use”- Juran
Dr. Juran’s ideas were instrumental in the development of the total quality management (TQM) theory, which is now a well-known base for quality initiatives. His book “The Quality Control Handbook” became the reference work for quality managers, and remains so to the present day.
He was one of the first people to recognize that the Pareto principle, which states that 80% of problems are caused by 20% of potential causes, applies to quality management and process improvement. From his observations, he developed Pareto analysis using a Pareto chart. Both Pareto analysis and Pareto charts are fundamental quality tools used in the application of Six Sigma.
Dr. Armand Feigenbaum
“Quality is defined by the customer’s opinion”- Faigenbaum.
Dr. Armand Feigenbaum has written many books on quality control and is credited with establishing the current concept of total quality control (TQC) from the earlier work by Dr. Juran. Dr. Feigenbaum’s concept of TQC insists that all employees in a company are involved in quality control, which is the same theory underlying Six Sigma.
Dr. Feigenbaum was the first person to promote the idea of zero defects as a performance goal, which is one of Six Sigma’s main goals.
Japanese Quality Gurus
Dr. Genichi Taguchi
“Quality is designed in, not inspected in.”- Taguchi
Dr. Genichi Taguchi, known as the “father of quality engineering,” was instrumental in developing quality engineering techniques that reduce cycle time, which is a large part of Six Sigma process improvement. Dr. Taguchi is well known for his theory that manufacturing processes are influenced by external factors, which he called “noise.” He said that to improve a process and reduce the costs involved, managers need to identify and eliminate noise from the “process signal” – the vital elements of the process.
“Quality in products involves the mistake proofing process or Poka Yoke – Shingo
Dr. Shigeo was one of the greatest influences on Japanese quality control and his contributions to quality improvement revolutionized the Japanese industrial sector and consequently influenced the industries in the west.
Dr. Kaoru Ishikawa
“Achieving quality involves understanding the causes of failure ” – Ishikawa
Dr. Kaoru Ishikawa is considered the “father of Japanese quality control,” . He was the first to distinguish the Japanese approach to total quality control from the Western style, which he called company-wide quality control (CWQC). Dr. Ishikawa’s ideas, such as the concept of quality circles and “next operation as customer”, are evident today in quality management.
Dr. Ishikawa’s major contribution to the development of the quality management theory is the development of the cause-and-effect diagram. His simple method and graphic made it easy to identify the root causes underlying process problems without using complicated statistics. The cause-and-effect diagram is known as the Ishikawa diagram in his honor.