(For more information, see the History of Quality.) The use of SPC methods diminished somewhat after the war, though was subsequently taken up with great effect in Japan and continues to the present day. The Relationship Between Statistical Quality Control and Statistical Process ControlДЄ marked increase in the use of control charts occurred during World War II in the United States to ensure the quality of munitions and other strategically important products. In addition to the basic 7-QC tools, there are also some additional statistical quality tools known as the seven supplemental (7-SUPP) tools: Cause-and-effect diagram (also called Ishikawa diagram or fishbone diagram).Known around the world as the seven quality control (7-QC) tools, they are: Kaoru IshikawaВ brought together a collection of process improvement tools in his text Guide to Quality Control. Although both terms are often used interchangeably, SQC includes acceptance sampling where SPC does not. Statistical process control (SPC) is the application of the same 14 tools to control process inputs (independent variables). Statistical quality control (SQC) is defined as the application of the 14 statistical and analytical tools (7-QC and 7-SUPP) to monitor process outputs (dependent variables). However, as more tests are employed, the probability of a false alarm also increases.

Various tests can help determine when an out-of-control event has occurred. Special cause variation, which stems from external sources and indicates that the process is out of statistical control.Common cause variation, which is intrinsic to the process and will always be present.A control chart helps one record data and lets you see when an unusual event, such as a very high or low observation compared with 'typical' process performance, occurs.Д¬ontrol charts attempt to distinguish between two types of process variation: Statistical process control is often used interchangeably with statistical quality control (SQC).ДЄ popular SPC tool is the control chart, originally developed by Walter ShewhartВ in the early 1920s. SPC tools and procedures can help you monitor process behavior, discover issues in internal systems, and find solutions for production issues. Statistical process control (SPC) is defined as the use of statistical techniques to control a process or production method. Quality Glossary Definition: Statistical process control

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