Safety performance upper control limit

The purpose of constructing the control chart is to graphically identify trends in data that indicate areas that must be addressed. When using control charts, safety managers will want to note data that is a trend or data that is out of control. Data that consistently falls between the upper and lower control limits, or data that is in control, may indicate that the control limits need to be recalculated with the more current data, thus tightening the control limits and thereby further improving the expected performance levels. 

---