ABSTRACT
Statistical process control (SPC) provides a statistical approach for evaluating processes and for improving the quality of these processes through elimination of special causes. When SPC is effectively implemented within a company, benefits can be derived through a reduced cost of manufacture, improved quality, fewer troubleshooting crises, and improved relationships with customers. Although manufacturing processes first come to mind, SPC can apply to any process. The control chart is the basic analytical tool of SPC and is used for first assessing a process, then for monitoring a process output with respect to on-target control and process variability. The purpose of SPC is to reduce variability and to improve the quality of process output. The use of SPC methods to evaluate and to improve processes not only can be applied to product characteristics such as tablet weight and tablet hardness, but also to product performance measures such as consumer complaints, line down time, and industrial safety measurements.
