In multivariate process control, Hotelling’s T 2 chart has been widely used. This allows to finding changes in the mean vector as a result of the flexibility needed to detect signals. By means of decomposing of a signal into orthogonal components, Mason, Young and Tracy have obtained an interpretation of this in the chart. Since the process is multivariate, any signal out of control is determined by one or more characteristics. The purpose of this paper is to evaluate the goodness of the decomposed reports to signal