SELF-STARTING CUMULATIVE SUM CHARTS: A SYSTEMATIC LITERATURE REVIEW OF APPLICATION AND RESEARCH DIRECTIONS

Statistical process control (SPC) tools are increasingly often utilized outside the field of industrial quality control. This paper gives attention to a SPC method that belongs to a special branch of methodologies called self-starting control charts. The method addressed here is the self-starting cumulative sum (SS-CUSUM) chart, the first self-starting method devised. CUSUM charts are powerful statistical tools designed to detect relatively small departures from specification. The self-starting variant can be utilized in case the specification is not known a priori. It relies on the running mean and standard deviation of all observations from process start onward to substitute for the unknown true values. The aim of this paper is to contribute to the ongoing utilization of SPC tools outside the field of quality control by identifying existing applications of SS-CUSUM charts discussed in the literature as well as current research directions. To meet these objectives, a systematic literature review was conducted. Two major sectors have been identified where SS-CUSUM charts are applied successfully outside industrial quality control: Agriculture and healthcare. Further, multiple studies have been found which address the inherent weaknesses of the SS-CUSUM chart and offer compensating measures. This study concludes that the SS-CUSUM chart has powerful monitoring capabilities that make it highly useful for various applications outside of industrial quality control and highlights opportunities for future research.