A review of nonstandard applications of statistical process control SPC charts

The principal application domain for statistical process control SPC charts has been for process control and improvement in manufacturing businesses. However, the number of applications reported in domains outside of conventional production systems has been increasing in recent years. Implementing SPC chart approaches in nonstandard applications gives rise to many potential complications and poses a number of challenges. This paper reviews nonstandard applications of SPC charts reported in the literature from the period 1989 to 2000, inclusive. Nonstandard applications are analysed with respect to application domain, data sources used and control chart techniques employed. Applications are classified into five groups according to the types of problem to which control chart techniques have been applied. For each group the nature of the applications is described and analysed. The review does not show a paradigm shift in the types of SPC control chart applications but does show clearly that the application boundaries extend considerably beyond manufacturing and that the range of problems to which SPC control chart techniques can be applied is much wider than commonly assumed. The paper highlights the critical fundamental and technical issues that need to be addressed when applying SPC chart techniques in a range of nonstandard applications. Wider managerial issues of importance for successful implementations in nonstandard applications of SPC control charts are also discussed.