Western Electric Rules

One way to codify abnormal behavior is the so-called Western Electric rules, which identify cases where a process is out of control ... 

Western Electric Rules Shewhart control charts can detect abnormal process behavior by comparing individual measurements with control chart limits. But the pattern of measurements can also provide useful information. For example, if 10 consecutive measurements are all increasing, then it is very unlikely that the process is in a... 

The Shewhart chart fails to detect tne 0.5a shift in A at k = 10. But the CUSUM chart quickly detects this change because a limit violation occurs at k = 20. The mean shift can also be detected by applying the Western Electric Rules in the previous section. 

Run rules, also known as Western Electric Rules [323], enable decision making based on trends in data. A process is declared out-of-control if any run rules are met. Some of the run rules are ... 

There are several specific rules that determine if a process is out of control. Some of the more widely used ones are the Western-Electric rules that state that a process is out of control if process data include... 

A wide variety of pattern tests (also called zone rules) can be developed based on the IID and normal distribution assumptions and the properties of the normal distribution. For example, the following excerpts from the Western Electric Rules (Western Electric Company, 1956 Montgomery and Runger, 2007) indicate that the process is out of control if one or more of the following conditions occur ... 

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