Control Charts enable the process owner to distinguish between measurements that are predictable within the inherent capability of the process $($common or system causes of variation$)$ and measurements that are unpredictable and produced by special causes of variation. The most critical data elements of the Control Chart are:

$$ Upper case, standard deviation, lower case

$$ Upper control limit$,$ center line $($mean$)$ and lower control limit

$x-$axis, $Y-$axis and percent complete

$$ Upper desired limit$,$ center$-$cut line $($average$)$ and lower desired limit