Alexander, Melvin T.; Macklin, Christine (1989, ASQC) Westinghouse Electric Corp., Glen Burnie, MD
Shewhart control charts have been a primary tool for monitoring process control for over 60 years. These charts are useful in tracing variations of processes to two sources. (1) natural or inherent causes and (2) special or assignable causes. American industry has recently rekindled interest in these charts because they have played an important role in the quality improvement successes of the Japanese. More advanced control charting tools have been developed since Shewhart charts, e.g., CUSUM and Geometric Moving Average (GMA) charts. Utilization of these more advanced techniques can aid America in improving its competitive edge. This paper will focus on the GMA chart which is particularly interesting because it provides a forecast of where a process will be in the next instance of time and allows the transition from a passive-monitoring role into an active-prediction role for process control improvement.
Statistics,Control charts,Geometric Moving Average (GMA) charts