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Statistical Process Control. The use of statistical methods to measure, analyze and improve processes.

Measurements can be taken at points within a process, not just at the end of a process. These measurements can then be examined and  analyzed. Improvements can then be made or recommendations made for when improvements should be made (i.e. allowing for variation and identifying where processes fall outside of acceptable tolerances).

SPC also involves a review of whether the correct measurements are being made. For example if the inputs and measurements from one batch to another are the same but the outputs different then that implies that something significant is not being measured.

SPC often makes use of "Control Charts" or "Run Charts" which plot one (or more) data values against outputs, often with ideal or best case data for comparison. This type of chart provides a visual comparison of the relationship between the measured values of two or more different variables.

SPC is an optimisation philosophy and does not refer to any specific statistical technique or method and the statistical methods used will vary according to the application domain.

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