The paper establishes the analytical grounds of the uniform superiority of a variable sampling interval (VSI) Shewhart control chart over the conventional fixed sampling interval (FSI) control chart, with respect to the zero-time performance, for a wide class of process distributions. We provide...

Purpose – The purpose of this paper is to examine the theoretical interface between statistical thinking, the statistical method of the control chart, and contemporary theories of organisational learning in regard to processes and their improvement. Design/methodology/approach – Theoretical...

In the last few years, multivariate quality control has been thoroughly studied. The control of the population means vector is usually obtained by using multivariate control charts developed for this purpose. Nevertheless, when the goal is the efficient control of the covariance matrix, few...

In the last few years, multivariate quality control has been thoroughly studied. The control of the population means vector is usually obtained by using multivariate control charts developed for this purpose. Nevertheless, when the goal is the efficient control of the covariance matrix, few...