Design and application of individuals and moving range control charts

Abstract

We evaluate the design of individuals and moving range charts through extensive simulations. Via a SAS program using 8000 replications, average run length is assessed for several shifts in process mean and variation. From these computations recommendations are made concerning when to use the individuals chart only, when to use a combined individuals and moving range chart, and the optimal design parameters when the combined approach is used. The paper includes discussion, recommendations, and examples concerning the monitoring of accounting data.