Control charts help analyze data for improving the manufacturing process.
The analysis of data using process behavior charts-Walter Shewhart called them control charts-is the foundation of statistical process control (SPC) for process improvement. SPC focuses on the concept that all processes have routine variation and some processes have additional variation from exceptions. Process improvement requires eliminating causes of exceptional variation, and reducing the variation from routine causes. Correctly constructed, process behavior charts separate exceptional variation from routine variation and allows a user to focus on identifying and removing exceptions from a process.
A variety of process behavior charts have been developed since Shewhart introduced the average and range chart in 1924. One that is widely used, both in manufacturing operations as well as for management processes, is the individuals and moving range chart.