The American Society for Quality Control (ASQC), in its Glossary and Tables for Statistical Quality Control, defines quality control as:

the operational techniques and the activities which sustain a quality of product or service that will satisfy given needs; also the use of such techniques and activities … the aim of quality is to provide quality that is satisfactory, e.g., safe, adequate, dependable, and economical.… [This requires] integrating several related steps including proper specification … design of the product… to meet the requirements; production [processes that] … meet the specification; inspection to determine [the degree of conformance] … to specification; and review of usage to provide for revision of specification [if necessary].

These steps are required for a firm to design, produce, market, and profit from a quality product. Control charts are one technique used in implementing, sustaining, and improving quality control. Statistical process studies are also an important tool in improving quality by reducing process variation. Other important techniques are experimental design and Taguchi methods. Total quality control (TQC) or total quality management (TQM) refers to quality control beyond the "sustaining" of quality. These last two concepts may lead to continual increases in quality.

Dr. Kaoru Ishikawa (1915-), recipient of many awards, including the Deming Prize, defined total quality control as a system of introducing and implementing quality technologies into various departments of a company, such as engineering, production, sales, and service, for the purpose of satisfying customers. He stated that viewed chronologically, TQC is only the first stage of company-wide quality control (CWQC). CWQC incorporates quality function deployment (QFD), whereas TQC does not. QFD is a design procedure that introduces quality control in product development. It is a formal mechanism that guarantees that "the voice of the customer" is heard throughout all the phases of manufacturing a product or providing a service.

As Dale Besterfield stated in his book Quality Control, the deliverance of a quality product or service requires the responsible integration of all the firm's departments— marketing, product engineering, purchasing, manufacturing engineering, manufacturing, inspection and testing, packaging and shipping, and product service. TQC or TQM is far more than sustaining quality, as it may include control systems, employee relations and organizational behavior, statistical process control, and Japanese management techniques.

Quality control techniques and standards, affecting almost all aspects of a business, have now been adopted at both national and international levels. The Malcolm Baldrige National Quality Award exemplifies the former. President Ronald Reagan signed the Malcolm Baldrige National Quality Improvement Act on August 20, 1987. The act was the culmination of a national campaign to improve the quality of goods and services in the United States. The award represents the highest level of recognition that an American company can receive.

On an international level, the ISO 9000 series of quality standards was first published in 1987. These standards reflect the importance of quality and reliability as critical factors for achieving and maintaining worldwide competitive advantage. Another example is the international environment management standard, ISO 14001. Companies worldwide use this standard as a blueprint to develop and refine internal environmental management systems.


Beginning in the Middle Ages, the maintenance of quality was generally guaranteed by the guilds. They required long periods of training, which instilled in craftsmen a strong pride in the quality of their work.

The Industrial Revolution initiated the specialization of labor. Consequently, workers no longer produced the whole product, only a part. This transformation led to a decline in workmanship. At first, quality was not greatly diminished since manufacturing processes were simple in the early days of the Industrial Revolution. As manufacturing processes became more complicated and work more specialized, however, the trend toward post-manufactured product inspection began.

During the 19th century, modem industrial systems arose. At this time in the United States, Frederick W. Taylor's (1856-1915) "scientific management" dominated. His philosophy placed work and production planning exclusively in the hands of management and industrial engineers. (The ultimate expression of Taylorism was Henry Ford's (1863-1947) moving assembly line.) Before scientific management, quality was manufacturing's responsibility. Since meeting production deadlines became the production manager's main priority, the responsibility for quality was placed increasingly in the hands of the "chief inspector" and the quality control department.

In 1924, at Bell Telephone Laboratories, Walter A. Shewhart (1891 1967) developed statistical control charts. These charts pinpointed the sources of variation within processes and were used to control the quality of, and to improve the processes that delivered, the output. It is a total quality management principle that, generally, quality is maintained and improved through the detection and reduction of process variation. Of course, it is assumed that the target value of the process has been obtained and maintained.

The introduction and implementation of Shewhart's control charts inaugurated statistical quality control. The value of statistical quality control became obvious during World War II. Unfortunately, American management failed to understand this value, and its brief and limited application was abandoned after the war as many companies viewed quality control as a wartime effort only. It seemed unnecessary in the booming postwar years when quantity was deemed to be all that mattered.

In 1946 the ASQC was founded. Under its auspices, quality professionals developed failure analysis methods to problem-solve, quality engineers became engaged in early product design, and a number of companies began to test the environmental performance of products.

In 1950 W. Edwards Deming (1900-1993), a statistician who had worked with Shewhart at Bell Labs, was invited by the Union of Japanese Scientists and Engineers (JUSE) to speak to Japan's leading industrialists. Deming presented a series of lectures on statistical quality techniques and on the responsibilities of top management for delivering quality products and services. The Japanese industrialists and engineers embraced Deming's teaching, and Japanese quality, productivity, and competitive position significantly increased. Under Deming, Joseph M. Juran (1904), and Armand V. Feigenbaum (1920-), the concept of quality control, no longer viewed as principally a corrective activity, was extended to all areas, from design to sales.

During the last four decades Japanese management and engineering professionals such as Ishikawa, Masaaki Imai, and Genichi Taguchi—the latter having formulated new statistical designs of experiment for quality—have expanded the theories of Deming, Juran, and R. A. Fisher. And in turn, American managers and statisticians have advanced the contributions of their Japanese counterparts.


A crucial aspect of CWQC is maintaining the quality of existing processes, of processes pertaining to new products or services, and of processes resulting from innovative technologies (discoveries based on new scientific principles). Of course, design of experiments can assure that the new product has quality built into it. Then the problem becomes one of maintaining and improving the quality. An example of an innovative technology is computer-aided design and computer-aided manufacturing (CAD CAM). These projects have revolutionized production systems.

A Japanese approach of improving and sustaining the quality of processes is known as kaizen (continuous improvement) technology. The activity of improving is included because kaizen technology assumes that any process based on innovative technology or other technology, is subject to steady deterioration (entropy) unless constant efforts are made to maintain and improve the process's standards. Kaizen technology is the accumulation of small technological improvements continually made upon the production or service process.

Dr. Donald J. Wheeler, coauthor of Understanding Statistical Process Control, further describes entropy: "Entropy is relentless. Every process will naturally and inevitably migrate toward the state of chaos. The only way this migration can be overcome is by continually repairing the effects of entropy." Having the ability to repair a process assumes that its effects are known. This knowledge can be achieved through control charts and process capability studies. Unlike today's common U.S. management practices, which are based on the Taylor model, kaizen technology requires virtually every employee's personal contribution and effort to quality. This requires a substantial management commitment of time and effort; infusions of capital are no substitute for this investment in time, effort, and people. Unlike the Taylor model, kaizen technology assumes that all employees can contribute to the improvement of the production processes both in terms of quality and productivity.

Taylor argued that all-important knowledge and information was known by management, and it was the exclusive responsibility of management to use "science" to establish an optimal production system. This optimal system was to be based on the close supervision of all work procedures. Workers were to follow, without deviation, the procedures proscribed by management. Their performances were to be judged on the basis of the standards of these procedures.

Cooperation within such a system meant that the workers would adhere to the directives of management. Taylor argued that if any deviations occurred, they were caused by the worker's failure to adhere to his job specifications. Many in management believe this is not "science" because there are sources of variation outside of the worker's control.

It is the opinion of a number of managers and scientists that management based on the Taylor model is incompatible with achieving, as kaizen technology does, long-run and long-lasting (but undramatic) quality improvements because such improvements come about only when workers are actively involved in the production processes. The kaizen approach asserts that those closest to the work have a great deal of skill, energy, and knowledge that must be tapped. Many believe the Taylor model ignores this workforce potential; it does not support the empowerment of employees. The kaizen approach stresses gradual and consistent changes and improvements as a result of both labor and management slowly learning more and more about the processes and systems in which they are involved. Kaizen technology has affected many other areas of business practices. In the field of accounting, Y. Kato has developed three cost categories to analyze and measure kaizen improvements. Such interactions among a company's departments are an essential element of CWQC.

Consequently, Japanese firms are committed to the notion that the customer comes first. For most U.S. firms, however, there is considerable doubt that this is so. Authors Kenneth Delavigne and J. Daniel Robertson state that, "despite lip service to the importance of the customer, observations still show that most companies concentrate on what they can get from customers (money, profits) than on what they are going to provide to the customer (the quality of the product, and extensions to the product such as spare parts, courteous support, a product line that grows with the customer's needs, and so on)."

Delavigne and Robertson use the term "neo-Taylorism" in describing current U.S. management practices, and conclude that "the state of management was even worse at the end of the 1980s than when the decade began." During the 1990s there was some improvement overall in U.S. management practices. At this time, however, all the evidence is not in to adequately evaluate U.S. management practices in the 1990s.



The first case is the Calsonic Corporation. Calsonic manufactures a "uniquely-designed flat motor" for automobiles. Instead of wire-wound magnetic cores, Calsonic uses laminated copper sheets that are perforated by high-speed stamping machines to form the electromagnetic circuitry. A French engineer conceived this technology used by Calsonic more than 25 years ago. He sold the rights to an American firm that was not able to commercialize it. Calsonic then purchased the rights and through a joint venture with the Yaskawa Electric Company found a way to manufacture the motor.

Calsonic feels that this manufacturing success was possible only due to kaizen technology. Many Calsonic employees made technological improvements on the original idea, especially in the areas of production engineering, precision stamping technology, product quality, assembly design, and machine maintenance.

The Calsonic Corporation's application of kaizen technology underlines Imai's observation that kaizen technology "includes those actions which make the best use of the resources at hand (such as people, machines, facilities, technology and so forth) … to improve little by little—the point is not to use money (unnecessarily)." Sustaining and improving the quality of output means quality control. For a firm to have the ability to do so requires TQM, and the application of such techniques as control charts and process capability studies. This is different from the common American managerial approach of attempting to find a quick fix, e.g., the attempt to find a new optimal situation by some new capital expenditure.

In the Calsonic example, employee involvement was critical. Kaizen technology, however, does not assume that workers and management have identical roles. Certainly, both labor and management spend time on quality improvement activities, with first-line supervisors and middle management spending the most time. But the kaizen approach asserts that workers spend the most time on maintenance activities that sustain quality. As one moves up the management ladder, that time decreases. Middle and top management spend far more time on innovative technology and new product development.

This is in contrast to the Taylor model, which asserts that workers must spend their time exclusively on maintenance and none on improvement. Therefore, management based on the Taylor model, according to many administrators, fails to tap the tremendous pool of information, knowledge, skill, and energy of workers.


The second example of sustaining and improving quality is dynamic random-access memory chips (DRAMs). Most of the technology for this high tech product was developed in the West, but today Japanese companies hold 75 percent of the world market.

The most important break-even factor for the manufacture of this product is the defective percentage. To control this factor, kaizen technology is necessary since any minor change in the manufacturing environment must be checked with great care to guarantee uniform production. At one Japanese plant, a small increase in the defective rate was noticed for a few hours one day. But, at first, no abnormal manufacturing conditions were discovered. Further investigation revealed the problem. A truck had parked by a ventilation tunnel for the DRAM plant's air conditioning system. The defective chips were caused by particles from the truck's exhaust. A new standard was introduced at the plant that prevented the problem from recurring. This new standard, obviously, resulted in sustaining and improving the quality of the output.


For quality control to occur, the top management of any company must have totally committed itself to TQC, and then CWQC. Sustaining and improving the quality of manufacturing or service processes require such tools as control charts, process capability studies, experimental designs, business ethics, organizational change and development, and excellent employee relations. Finally, to compete internationally a company has to adopt international quality standards.

[ Peter B. Webb , Ph.D. ]


Aeppel, Timothy. "More, More, More: Rust-Belt Factory Lifts Productivity, and Staff Finds It's No Picnic." Wall Street Journal, 18 May 1999, Al.

American Society for Quality Control. Statistics Division. Glossary and Tables for Statistical Quality Control. Milwaukee, WI: American Society for Quality Control, 1983.

Besterfield, Dale H. Quality Control. New York: Prentice Hall, 1990.

Bossert, James L. Quality Function Deployment: A Practitioner's Approach. Madison, WI: ASQC Quality Press, 1991.

Box, G. E. P., William G. Hunter, and J. Stuart Hunter. Statistics for Experimenters: An Introduction to Design, Data Analysis, and Model Building. New York: John Wiley & Sons, 1978.

DeCarlo, Neil J., and W. Kent Sterett. "History of the Malcolm Baldrige National Quality Award." Quality Progress, March 1990, 21-27.

Delavigne, Kenneth T., and J. Daniel Robertson. Deming's Profound Changes: When Will the Sleeping Giant Awaken? Englewood Cliffs, NJ: PTR Prentice Hall, 1994.

Deming, W. Edwards. Out of the Crisis. Cambridge, MA: MIT Center for Advanced Engineering Studies, 1986.

DeVor, Richard E., and others. Statistical Quality Design and Control. New York: Macmillan, 1992.

Feigenbaum, Armand V. Total Quality Control. Madison, WI: American Society for Quality Control, 1991.

Gitlow, Howard, and others. Tools and Methods for the Improvement of Quality. New York: Irwin, 1989.

Hemenway, Caroline G., and Gregory J. Hale. "The TQEMISO Connection." Quality Progress, June 1996, 29-32.

Imai, Masaaki. GEMBA Kaizen: A Common Sense, Low-Cost Approach to Management. New York: McGraw-Hill, 1997.

- Kaizen: The Key to Japan's Economic Success. New York: Random House Business Division, 1986.

Ishikawa, Kaoru. Guide to Quality Control. Boston: Asian Productivity Organization, 1987.

——. "Quality and Standardization Programs for Economic Success." Quality Progress, January 1984, 16-20.

Kato, Y. "Target Costing Support Systems: Lessons from Leading Japanese Companies." Management Accounting Research, April 1993, 43-44.

Lochner, Robert H., and Joseph E. Matar. Designing for Quality: An Introduction to the Best of Taguchi and Western Methods of Statistical Experimental Design. Madison, WI: ASQC Quality Press, 1990.

O'Neil, James P. "Using ISO 9000 to Go beyond Industrial Norms." Quality Progress, December 1998, 43-44.

Taylor, Frederick W. The Principles of Scientific Management. New York: Harper & Row, 1911.

Thurow, Lester C. "A Weakness in Process Technology." Science, 18 December 1987, 1659-63.

Wheeler, Donald J., and David S. Chambers. Understanding Statistical Process Control. Knoxville, TN: Statistical Process Controls, 1986.

Wilson, Lawrence A. "Eight-Step Process to Successful ISO 9000 Implementation: A Management System Approach." Quality Progress, January 1996, 37-40.

Yoshida, Shuichi. "Two Technological Developments." Kaizen Communique, January 1990, 3.

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