On Small Shifts in Quality Control

Douglas M. Hawkins, K. D. Zamba

Research output: Contribution to journalArticlepeer-review

18 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 languageEnglish (US)
Pages (from-to)143-149
Number of pages7
JournalQuality Engineering
Volume16
Issue number1
DOIs
StatePublished - Sep 1 2003

Keywords

  • CUSUM
  • EWMA
  • Loss function
  • Run length
  • Shewhart control chart

Fingerprint Dive into the research topics of 'On Small Shifts in Quality Control'. Together they form a unique fingerprint.

Cite this