SCV is detected using the following rules
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System shifts | Six or more consecutive points either all above or all below the mean line. |

Trends | Five or more consecutive increasing or decreasing points. |

Too many/too few runs | The number of times data crosses the mean line is too many or too few (based on the total number of observations).9 |

Astronomical points | Data points outside control limits that are obviously different from the rest of the points; all studying the chart would agree the point is unusual. |