Basic control charts such as the Xbar-R and X-MR by Dr. Walter A. Shewhart have been in use since the 1920s. The limitations of these control charts are that they are not effective to detect small shift of 1.5 sigma or less. Hence, when small shifts are to be measured, alternatives such as the Cumulative-Sum (CUSUM) & Exponentially Weighted Moving-Average (EWMA) are better options.
This course covers the CUSUM and EWMA control charts, as well as the different methods to compute process capability where the process does not follow normal distribution.