變動抽樣間隔的方法便是在製程穩定時，可以延長抽樣間隔，當製程失控時，可以縮短抽樣間隔，如此對製程監控有所幫助。本文應用MSE（Mean Square Erro）管制圖對製程變異與製程目標值偏移的偵測，探討製程一開始便發生特殊原因時的偵測效果，研究發現採用變動抽樣間隔MSE管制圖進行製程監控的偵測速度會較固定抽樣間隔MSE管制圖為佳。

Variable sampling interval is helpful for process control and can extend the sampling interval when the product process is stable, otherwise it will reduce the sample when the process is out of control. This paper applies MSE control chart on shift's detection of the process variation and process target value. Consider the beginning of process production it may have the detection effect for special cause. This study found using variable sampling interval control charts is better than a fixed sampling interval control chart to monitor MSE detection rate.