Statistical Process Control

Definition
Outputs from a manufacturing process will vary - perhaps minutely - from the exact specification, and deliveries from a service will differ in quality and substance. These inconsistencies in quality require constant monitoring to see if they are random, regular, haphazard, important, or evidence of a problem. The monitoring and controlling should be applied to the process not the product, and can be greatly facilitated by S.P.C.
Process control means controlling production by checking its quality while the work is still in process. Implementing S.P.C. means applying statistical techniques and analysis to that control function. As S.P.C. is about measuring the quality of work in process, its implementation is usually allied to techniques related to quality systems management.
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