Confirmation sample control charts

Traditional (X) over bar and R control charts are used widely in industry, but do not respond quickly to small or moderate changes in the process outp ut. Confirmation sample control (CSC) charts to detect changes in the proce ss mean and process variability are proposed. These new control charts have substantially better operating characteristics than (X) over bar and R cha rts. CSC charts require that any unusual observed sample be confirmed throu gh an independent confirmation sample taken from the process. This makes CS C charts appealing to production personnel since the charts require the ver ification of bad news. The implementation of CSC charts is illustrated, and figures are given that allow the determination of appropriate design param eters.