Title: A statistical control chart for monitoring customer waiting time

Authors: Xiaofeng Zhao; Kenneth Gilbert

Addresses: College of Business, University of Mary Washington, Fredericksburg, VA 22401, USA ' Department of Statistics, Operations and Management Science, College of Business Administration, University of Tennessee, Knoxville, TN 37996, USA

Abstract: Statistical control charts, which signal an out-of-control condition when a single point falls beyond a three-sigma limit, have been the standard control charts for variables and attributes. However, statistical process control-based monitoring of performance measures of queuing systems has eluded mainstream practices within the quality management discipline. One major reason is that there are no general theoretical formulae existing that may provide a platform to calculate control limits for a general queue. In this paper, a statistical control chart is developed for the waiting time in the GI/G/1 queue. A significant feature of the method is that it is mathematically tractable and can be implemented in a spreadsheet format.

Keywords: statistical process control; SPC; control charts; customer waiting times; queuing theory; approximation methods; waiting time monitoring.

DOI: 10.1504/IJDATS.2015.071366

International Journal of Data Analysis Techniques and Strategies, 2015 Vol.7 No.3, pp.301 - 321

Published online: 22 Aug 2015 *

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