A METHOD OF OPERATING A PROCESS OR MACHINE

An operator tool is provided to assist an operator of a process or machine in decision making. The tool is initiated by the operator selecting a key variable, "Variable of Interest", at the user interface. The variable of interest usually is an output variable of interest (such as quality, cost, etc.). At least most significant variables related to the selected variable of interest are automatically determined by a statistical method and shown at the user interface. The operator can adjust the related variables shown on the interface. The impact of one variable to another is demonstrated by a prediction method and shown in a numerical and/or graphical form. After being satisfied with the result of the analysis, the operator decides on which is the preferred parameter change in order to overcome the problem in question or achieve the desired improvement, and then implements the corresponding change on the real system.