Abstract: A method of establishing a process decision support system. Decision support systems of the kind are used in manufacturing processes, particularly industrial manufacturing processes, to monitor the performance of the processes in view of controlling the processes in order to optimise process production and quality. The method includes collecting process data of a process, collecting operational data of a process, and fusing the process data and operational data to create a fused data set (such as a consolidated rule set) of the process upon which process decisions (such as control decisions) may be taken. The process data and operational data may be fused according to methods of rules-based knowledge fusion, mathematical knowledge fusion, or case-based reasoning knowledge fusion.