Statistical Process Control: A Method Of Statistical Process Management

Statistical Process Control (SPC) is a method of quality control that uses statistical means in order to improve a process. In general, SPC the process inspects random samples of output and determines whether or not the process is producing within an acceptable range – this will be elaborated upon later. Originating in the 1920s, a physicist, Walter Shewhart, analyzed variation in production processes[i]. Shewhart understood variation was inherent within a production process, but instead focused on “common causes” in the processes ultimately leading to the creation of simple models to control certain variable and improve processes[ii]. The majority of work in regards to SPC was considered theoretical until combined with Total Quality Management

The goal of these organizations is to produce their outputs at an acceptable cost and to provide goods and services which conform to the requirements of the customer (xiv). In order to be viable these organizations must satisfy their customer, produce products of a competitive quality and remain profitable. Most manufacturers would define quality as a product that conforms to certain physical characteristics set down within a particularly tight specification, while customers of the organization would define a quality product as one that meets their requirements (xiv). In order to satisfy the customer, the organization must meet the requirements of the customer by ensuring that the product that the customer receives conforms to the standards of the product. To ensure that the product meets the company’s quality standards the products must be checked and inspected. If the product fails to meet quality standards it may have to be scrapped or reworked and then re-examined. If the customer receives a subpar product, the company will incur external failure costs such as warranty claims, customer complaints and the loss of goodwill (xiv). A poor manufacturing process will result in high external and internal failure costs and high appraisal costs. By using SPC to improve the manufacturing process, the organization can reduce these costs and increase