Stability assessment with the stability index

Abstract Assessment of process stability is an important way to ensure high quality. There have been various approaches in the literature to assess process stability. We describe these methods and provide a minor modification of a previous approach, which we call the stability index (SI). We provide justification for the SI as a best practice for practitioners who assess process stability. We provide examples of the computation of the SI for various scenarios and show how the SI can be used in conjunction with capability indices in a process performance graph.

[1]  Yerriswamy Wooluru,et al.  Journal of Modern Applied Statistical Methods Approaches for Detection of Unstable Processes: a Comparative Study Approaches for Detection of Unstable Processes: a Comparative Study Approaches for Detection of Unstable Processes: a Comparative Study , 2022 .

[2]  Charles W. Champ,et al.  Design Strategies for Individuals and Moving Range Control Charts , 1994 .

[3]  Kimberly Vukovinsky.  Beyond Capability Confusion , 2000, Technometrics.

[4]  Samuel Kotz,et al.  Process Capability Indices , 1993 .

[5]  Lloyd S. Nelson,et al.  Control Charts for Individual Measurements , 1982 .

[6]  Keith A. Britt,et al.  Process monitoring using statistical stability metrics: Applications to biopharmaceutical processes , 2016 .

[7]  George C. Runger,et al.  Quantitative Techniques to Evaluate Process Stability , 2006 .

[8]  Connie M. Borror,et al.  Two‐dimensional guidelines for measurement system indices , 2011, Qual. Reliab. Eng. Int..

[9]  William H. Woodall,et al.  Statistical process control with several components of common cause variability , 1995 .

[10]  Fred Spiring,et al.  Introduction to Statistical Quality Control , 2007, Technometrics.

[11]  Bovas Abraham,et al.  Understanding Process Capability Indices , 1998 .

[12]  Willis A. Jensen.  Signal: Understanding What Matters in a World of Noise , 2016 .

[13]  STANDARD DEVIATION: ROOT MEAN SQUARE VERSUS RANGE CONVERSION , 1989 .

[14]  Susanta Kumar Gauri,et al.  A Quantitative Approach for Detection of Unstable Processes Using a Run Chart , 2010 .

[15]  John Sall,et al.  Scaling-up process characterization , 2018 .

[16]  Benjamin M. Adams,et al.  Advanced Topics in Statistical Process Control : The Power of Shewhart's Charts , 1995 .

[17]  Steven E. Rigdon,et al.  COMPARING TWO ESTIMATES OF THE VARIANCE TO DETERMINE THE STABILITY OF A PROCESS , 1992 .

[18]  Donald J. Wheeler,et al.  Understanding Statistical Process Control , 1986 .

[19]  G. Geoffrey Vining,et al.  A tutorial on an iterative approach for generating Shewhart control limits , 2016 .