Performance evaluation of two methods for online monitoring of linear calibration profiles

Abstract

We compare the performance of two phase II monitoring schemes for linear profiles, one based on the classical calibration method monitoring the deviations from the regression line (referred to as the NIST method) and the second based on individually monitoring the parameters of the linear profile (referred to as the KMW method). The comparison criterion is average run length performance under different sustained shifts in the intercept, slope and error standard deviation of the linear calibration line. A simulation study shows that the NIST method performs poorly compared to the combined control charting scheme of the KMW method.

Keywords:

• Average run length
• Profile monitoring
• Simple linear regression
• Statistical process control

Acknowledgments

This work was supported by National Science Foundation grants DMI-0354859 and DMI-0354866. The authors appreciate the helpful comments of the anonymous reviewers.