Robust control charts for time series data
This article presents a control chart for time series data, based on the one-step-ahead forecast errors of the HoltWinters forecasting method. We use robust techniques to prevent that outliers affect the estimation of the control limits of the chart. Moreover, robustness is important to maintain the reliability of the control chart after the occurrence of alarm observations. The properties of the new control chart are examined in a simulation study and on a real data example.
robustness control chart holtwinters non-stationary time series outlier detection statistical process control