1. A system for monitoring a process determined by a set of process data in a multidimensional process data domain pertaining to process input-output data, the system comprising: means for acquiring a plurality of historic process data sets; means for obtaining a transformation from the multidimensional process data domain to a model data domain of lower dimension by performing multivariate data analysis; means for transforming a current process data set to a model data set to monitor the process using the obtained transformation; and means to detect a permanent change of a process characteristic of the process which is no longer captured by the multivariate data analysis based on observing Residuals exceeding a predetermined threshold for a predetermined amount of time.