Gauge imprecision, control charts and environmental monitoring

Monitoring algorithms, such as the Shewhart and Cusum control charts, are often used in environmental monitoring. The statistical properties of these algorithms are known to be highly responsive to measurement errors. Recent studies have underlined the important role played by the two-component measurement error model in environmental analyses. In this work, we utilize simulations to study the effects of the two-component error model on the performance of the Shewhart control chart for the process mean. The results reveal that gauge imprecision may seriously alter the statistical properties of the control chart.