On Small Shifts in Quality Control

Douglas M. Hawkins; K. D. Zamba

doi:10.1081/QEN-120020780

On Small Shifts in Quality Control

Douglas M. Hawkins, K. D. Zamba

Statistics (Twin Cities)

Research output: Contribution to journal › Article › peer-review

22 Scopus citations

Abstract

The Shewhart Xbar chart is effective in detecting large shifts in a process but unable to find moderate shifts. We show that this blind spot allows shifts smaller than one standard deviation to continue undetected for long periods, thereby incurring much larger total costs than do rapidly detected large shifts. Augmenting the Shewhart chart with a cumulative sum chart largely plugs this gap, leading to much more effective process monitoring.

Original language	English (US)
Pages (from-to)	143-149
Number of pages	7
Journal	Quality Engineering
Volume	16
Issue number	1
DOIs	https://doi.org/10.1081/QEN-120020780
State	Published - Sep 2003

Bibliographical note

Funding Information:
The authors are grateful for the editor’s suggested improvements. This work was supported by the National Science Foundation under grant DMS 9803622.

Keywords

CUSUM
EWMA
Loss function
Run length
Shewhart control chart

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10.1081/QEN-120020780

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keywords = "CUSUM, EWMA, Loss function, Run length, Shewhart control chart",

author = "Hawkins, {Douglas M.} and Zamba, {K. D.}",

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KW - EWMA

KW - Loss function

KW - Run length

KW - Shewhart control chart

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On Small Shifts in Quality Control

Abstract

Bibliographical note

Keywords

Publisher link

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