Quality control: History

Craft and tradespersons

During the Middle Ages, guilds took the responsibility of quality control upon themselves. All practitioners of a particular trade living in a certain area were required to join the corresponding guild, and the guild instituted punishments for members who turned out shoddy products.

Royal governments purchasing material were interested in quality control as customers. For instance, King John of England appointed a certain William Wrotham to supervise the construction and repair of ships. Some centuries later, but also in England, Samuel Pepys, Secretary to the Admiralty, appointed multiple such overseers.

Prior to the extensive division of labor and mechanization resulting from the Industrial Revolution, it was possible for a workman to control the quality of his own product. Working conditions then were more conducive to professional pride.

The Industrial Revolution led to a system in which large groups of men performing a similar type of work were grouped together under the supervision of a foreman who also took on the responsibility to control the quality of work manufactured.

Quality Assurance has developed a good deal during the last 80-90 years (in about 20 year intervals) from its inception to the current state of the art.

Wartime production

During World War I, the manufacturing process became more complex, and the introduction of large numbers of workers being supervised by a foreman designated to ensure the quality of the work, which was being produced. This period also introduced mass production and piecework, which created quality problems as workmen could now earn more money by the production of extra products, which in turn led to bad workmanship being passed on to the assembly lines.

Due to the large amount of bad workmanship being produced, the first full time inspectors were introduced into the large-scale modern factory. These full time inspectors were the real beginning of inspection quality control, and this was the beginning the large inspection organizations of the 1920’s and 1930’s, which were separately organised from production and big enough to be headed by superintendents.

The systematic approach to quality started in industrial manufacture during the 1930’s, mostly in the USA, when some attention was given to the cost of scrap and rework. With the impact of mass production, which was required during the Second World War, it became necessary to introduce a more stringent form of quality control which can be identified as Statistical Quality Control, or SQC. Some the initial work for SQC is credited to Walter A. Shewhart of Bell Labs.

This system came about with the realisation that quality cannot be inspected into an item. By extending the inspection phase and making inspection organizations more efficient, it provides inspectors with control tools such as sampling and control charts.

SQC had a significant contribution in that it provided a sampling inspection system rather that a 100 per cent inspection. This type of inspection however did lead to a lack of realisation to the importance of the engineering of product quality.

For example, if you have a basic sampling scheme with an acceptance level of 4%, what happens is you have a ratio of 96% products released onto the market with 4% defective items – this obviously is a fair risk for any company/customer – unless you happen to be one of the unfortunate buyers of a defective item.

Postwar

After World War II, the United States continued to apply the concepts of inspection and sampling to remove defective product from production lines. However, there were many individuals trying to lead U.S. industries towards a more collabrative approach to quality. Excluding the U.S., many countries' manufacturing capabilities were destroyed during the war. This placed American business in a position where advances in the collabrative approaches to quality were essentially ignored.

After World War II, the U.S. sent General Douglas MacArthur to oversee the re-building of Japan. During this time, General MacArthur invited two key individuals in the development of modern quality concepts: W. Edwards Deming and Joseph Juran. Both individuals promoted the collabrative concepts of quality to Japanese business and technical groups, and these groups utilized these concepts in the redevelopment of the Japanese economy.

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