A set of measurement techniques used to monitor a process in order to assess variability of performance and allow for predictions of when corrective action needs to be taken to prevent a problem from occurring. It uses data collected from various points within the process. Variations that may affect the quality of the end product or service are detected and corrected. The emphasis is on early detection and the prevention of problems. Multivariable process control is a form of statistical process control that uses a set of manipulated and control variables to control a process plant.