Multivariate Control Charts
Monitor Multiple Process Characteristics Simultaneously
Univariate control charts monitor a single process characteristic, whereas multivariate control charts monitor multiple process characteristics. Independent variables can be charted individually, but if the variables are correlated, a multivariate chart is needed to determine whether the process is in control. Multivariate control charts can detect shifts in the mean or the relationship between several related variables.
Figure 6.1 Example of a Multivariate Control Chart