Statistical Process Control is developed in the 1920’s by Walter Shewart at Bell Telephone Laboratories. It started as an investigation to develop a scientific basis for attaining economic control of quality of manufacturing product through the establishment of control limits to indicate at every stage in the production process from raw materials to finished product when the quality of product is varying more than is economically desirable as Walter Shewart states it in his preface of the book resulting from this investigation.
The book “Economic Control of Quality of Manufactured Product” was published in 1931 and all concepts described in this book are still valid more than 80 years later. The methods described by Shewart were incorporated into a management philosophy by Dr. W.E. Deming (a younger colleague of Shewhart).
Just prior to World War II American industrial management did not pay very much attention to Deming and his views on statistical techniques and open management style. However Japan’s post war efforts to increase production, and to compete with western industries, found Deming’s philosophy attractive. Top Japanese management concluded that they had to improve quality, and invited Deming to lecture in Japan in the early 1950’s. The successful tour lead to a few companies implementing the Deming methodologies and within a few months their quality and productivity increased. This in turn led to a greater proliferation of these techniques in Japan. It was the commitment of top Japanese management, the realization of the rewards of SPC implementation plus the philosophies of Deming that are the basis of Japanese competitive advantage as we know it today. Deming stated that a quality product can only be made if all the processes in a company are under control, therefore everybody in a company is responsible for quality. The knowledge on the shop floor has to be used and the walls between departments have to be torn down. It is the responsibility of management to allow operators to work with the best methods, the best machines, etc. In 1981 Deming appeared in a documentary on American television named: “If Japan can, why can’t we?” There was a considerable reaction and for the first time managers in America listened to his philosophy. It was quickly proven that SPC could also give beneficial results in western industries. However despite increased attention on this side of the globe SPC is still in a preliminary implementation stage. Deming has summarized his philosophy in 14 rules of management. These rules are given below:
14 rules of management:
- Create constancy of purpose toward improvement of product and service with the aim to become competitive, stay in business and provide jobs.
- Adopt the new philosophy. We are in a new economic age, created by Japan. A transformation of Western style of management is necessary to halt the continued decline of industry.
- Cease dependence on inspection to achieve quality. Eliminate the need for mass inspection by building quality into the product in the first place.
- End the practice of awarding business on the basis of price. Purchasing, design, manufacturing and sales departments must work with the chosen suppliers so as to minimize total cost, not initial cost.
- Improve constantly, and forever, every activity in the company so as to improve quality and productivity and thus constantly decrease costs.
- Institute education and training on the job, including management.
- Institute improved supervision. The aim of supervision should be to help people and machines do a better job.
- Drive out fear so that everyone may work effectively for the company.
- Break down the barriers between departments. People in research, design, sales and production must work as a team to tackle production and usage problems that may be encountered with the product or service.
- Eliminate slogans, exhortations and targets for the workforce asking for new levels of productivity and zero defects. The bulk of the causes of low quality and low productivity belong to the system and will not be in the direct control of the workforce.
- Eliminate work standards that prescribe numerical quotas. Instead, use resources and supportive supervision, using the methods to be described for the job.
- Remove the barriers that rob the hourly worker of the right to pride of workmanship. The responsibility of supervision must be changed from sheer numbers to quality. Equally, remove barriers that rob people in management and engineering of their right to pride of workmanship.
- Institute a vigorous program of education and retraining. New skills are required for changes in techniques, materials and services.
- Put everybody in the organization to work in teams to accomplish the transformation.