Various rules

• Within the control limits: whenever a part is measured that falls within control limits the perfectly centered process hypothesis is completely verified. No futher action is required.
• Outside of control limiits: whenever a part is measured that falls outside of the control limits the perfectly centered process hypothesis is not verified. The process must, therefore, be adjusted. Using the rules defined above allows for variation detection in finer processes.

Graph	Description	Meanvalue chart decision	Range chart decision
	Controlled procedures The curves and the oscillating R from each side of the mean. . 2/3 of the points are in the central third of the chart.	Production	Production
	Points outside of the limits The last point traced surpassed the control limits	Adjusting the procedure by the difference value that separates the point from the target value.	Upper limit case The short-term capability deteriorates. It is necessary to find the source of this deterioration and intervene.. There is a measurement error
	Upper or lower trend 7 consecutive points are above or below the mean.	Adjusting the procedure by the mean difference that separates the trend from the target value	Upper trend case The short-term capability deteriorates. It is necessary to find the source of this deterioration and intervene.. Lower trend case The short-term capability improves. It is necessary to find the source of this improvement and maintain it.
	Increasing or decreasing trend 7 consecutive points show a regular increase or a regular decrease.	Adjusting the procedure if the last point approaches the control limit of the difference that separates the last point from the target value	Ascending series case The short-term capability deteriorates. It is necessary to find the source of this deterioration and intervene.. Descending series case The short-term capability improves. It is necessary to find the source of this improvement and maintain it.
	1 point is close to the limit. The last traced point within 1/6 of the edge of the control chart.	Confirm by taking another sample immediately. If the point reappears in the central third - production. If the point is also close to the limits or outside of the limits, adjust the meanvalue of the two points	Upper parameter case Monitor the capability. If several of the points on the chart are also close to the upper limits, the capability deteriorates. It is necessary to find the source of this deterioration and intervene.