| Parameter,Description | |
| μ_in,"The mean of the performance metric when the process is in-control, i.e., when there is no performance drift" | |
| ARL_0,Number of observations before the control chart signals a false detection | |
| σ_in,The in-control standard deviation of the metric | |
| ARL_1,Number of observations before the control chart signals a true detection | |
| k,"The normalized reference value, which is related to the magnitude of change that one is interested in detecting. k = 0.5 is the default choice for detecting a unit standard deviation change" | |
| S_hi,Cumulative sum of positive changes in the metric | |
| h,The normalized threshold or control limit (default =4). This threshold determines when the control chart signals a detection | |
| S_lo,Cumulative sum of negative changes in the metric |