Multivariate Process Capability Indices: A Directional Approach

Abstract

We propose a unified, universal, natural, and very intuitive way how to obtain new multivariate and tool wear extensions of univariate process capability indices by means of projection pursuit. We also illustrate the methodology in detail of the popular precision and accuracy indices, generalize the latter in a few different ways in the same spirit, add some personal insight, discuss the computational issues involved, and demonstrate the advantages of our approach in a small data example.

Keywords:

• Process capability index
• Projection pursuit
• Quantile regression.

Mathematics Subject Classification:

• Primary 62P30
• Secondary 62H99.