In order to optimize the number of controls in semiconductor manufacturing, a Permanent Index per Context (IPC) has been developed to evaluate in real-time the risk on production tools. Depending on the context which can be defined at tool level, chamber level or recipe level, the IPC allows a very large amount of data to be managed and helps to compute global risk indicators on production. A prototype based on the IPC has been developed and deployed for the CMP workshop. Results show that various indicators can be determined in real time to control risks. The number of measurements without actual added value can be strongly reduced. Moreover, the dispatching of lots on production tools can be improved.