SPC embraces a management philosophy of continuous process improvement that has a primary focus on prevention of defects. After a process has been characterized using statistical techniques (i.e., design experiments (DOE), capability studies, etc.), SPC is a tool that can be applied to control and optimize the process and reduce variability. An acceptable approach toward an SPC system involves the use of 'end-of-process' data to control the process through the application of SPC techniques. However, the intent of this standard is to emphasize the use of in-process data in order to better control and forecast system quality. This proactive use of SPC in conjunction with other techniques and the appropriate responsiveness to out-of-control situations serves to make SPC techniques critical in continuous process improvement and achieving excellence.