Comparison of three multivariate process capability indices

Process capability analysis often entails characterizing or assessing proce sses or products based on more than one engineering specification or qualit y characteristic. When these variables are related characteristics, the ana lysis should be based on a multivariate statistical technique. In this expo sitory paper, three recently proposed multivariate methodologies for assess ing capability are contrasted and compared. Through the use of several grap hical and computational examples, the information summarized by these metho dologies is illustrated and their usefulness is discussed.