Control chart

A control chart is a graph that uses data about a process to help you understand how it's working. It's like a graph that shows you how consistent the process is. The control chart has two lines. One line is the average and the other is the upper and lower limits. The average line shows what the average of the process is and the upper and lower lines show where the process should be. The control chart tells you if the process is working as it should. If the process is working well, the points on the chart should stay between the upper and lower lines. When the points go outside the lines, it means there is a problem and we need to fix it.