The present invention relates to a method and to any system using such a
method for performing statistical process control on the basis of taking
indicators or measurements on the inputs, the outputs, and the control and
operating parameters of said process, and which can be represented by
observation points in frames of reference associating their values to
their sampling indices. In the invention, the observed values are
transformed so that the resulting values are compatible with the
multidimensional Gaussian distribution model; said transformed observation
points are situated in a multidimensional space, each dimension being
associated with a measured magnitude; the out-of-control observation
points situated in this way and concentrated in a particular direction are
identified; and said direction is associated with a common cause for drift
in said process, and each observation-and-anomaly pair is associated with
indicators in order to propose zero, one, or more causes of anomaly that
might relate to the observation made.
