Chan, Lai K.; Cheng, Smiley W.; Spiring, Fred A. (1988, ASQC) The University of Manitoba, Winnipeg, Manitoba, Canada
A graphical technique for monitoring process capability is proposed that allows practitioners to (a) assess the assumption of normality, (b) identify departures from the target value, (c) measure process variability, (d) measure process capability (Cpm or Cpk) and (e) monitor the on-going ability of a process at various times in its history. The procedure is simple and inexpensive to use while being easily interpretable. It makes use of common statistical procedures which very often are already being used in process capability studies.