Group Runs Control Chart for Process Variability using Auxiliary Information

By : V. B. Ghute , S. A. Pawar , C. G. Gardi

Page No: 160-189

Abstract:
Recent studies have demonstrated that Auxiliary Information Based (AIB) control charts can significantly enhance the run length performance of control charts. Furthermore, the Group Runs (GR) control charts as an extension of the synthetic control charts are recommended for quickly detecting shifts in the process parameters. In this paper, AIB-GR control chart as a combination of Shewhart-type AIB chart and an extended version of the CRL chart is proposed for efficiently monitoring process variability shifts using auxiliary information. The charting statistic of proposed chart requires information from the study and correlated auxiliary variables. The construction, optimal design and implementation of the proposed chart are discussed in detail. The zero-state and steady-state performance of the AIB-GR chart is evaluated using the average run length and standard deviation of the run length criteria and is compared with Synthetic-type AIB chart.ItturnsoutthattheproposedAIB-GRcontrolchartunder zero-state mode performs uniformly better than AIB-synthetic chartfor all shift sizes and level of correlation between study and auxiliary variables, however under steady-state mode proposed AIB-GR chart perform better than that of AIB-synthetic chart only for small shifts in process variability. The implementation of theproposedchartisillustrated with an example. Based on the significant improvement in the ARL performance, the AIB-GR chart is recommended for the detection of the shifts in the process variability.

Authors
V. B. Ghute: Punyashlok Ahilyadevi Holkar Solapur University, Solapur, 
S.A. Pawar:  Punyashlok Ahilyadevi Holkar Solapur University, Solapur, 
C. G. Gardi Punyashlok Ahilyadevi Holkar Solapur University, Solapur, 
 

DOI: https://doi.org/10.32381/IAPQRT.2026.50.02.3