A Note on the Multivariate Process Capability Index MCpm. (12th November 2013)

• Record Type: Journal Article
• Authors: Scagliarini, Michele
• Is Part Of: Quality and reliability engineering international. Volume 31:Number 2(2015:Mar.)
• Page Start: 329
• Page End: 339
• Publication Date: 2013-11-12
• Subjects: Reliability (Engineering) -- Periodicals; Quality control -- Periodicals; High technology -- Periodicals; 620.00452
• DOI: 10.1002/qre.1592
• Languages: English
• ISSNs: 0748-8017

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Important features of multivariate process capability indices are comparability, interpretability and ease of implementation. When poor process capability is indicated by an index, the user should determine why the process is incapable (e.g. excessive variability or off‐target process mean). One of the most used multivariate process capability indices is <italic>MC</italic>_{<italic>pm</italic>} because it provides assessments of process precision and accuracy. In this work, we study and discuss a peculiarity of <italic>MC</italic>_{<italic>pm</italic>}: processes that are equivalent in terms of precision, accuracy and <italic>MC</italic>_{<italic>pm</italic>} index, after the occurrence of the same increase in the process variability, can have different values of the index. Because <italic>MC</italic>_{<italic>pm</italic>} is often used for comparing processes, this behaviour may cause comparability difficulties. Therefore, we suggest how to take into account this specific behaviour for avoiding erroneous conclusions. Copyright © 2013 John Wiley &amp; Sons, Ltd.</p> </abstract>