Limits and “Alarm index”, from monovariate to GPC
Should we give up control charts when we find ourselves faced with “non-standard” situations that do not verify the hypotheses of use of the MSP? On the AFNOR standard side, no response. Daniel Lafaye de Micheaux proposes here a clarification of the definition of the limits to be used for process control. Going beyond the framework of the classic monovariate MSP, this definition introduces the notion of specific multivariate indicators of anomaly and that of Alarm Index, specific to the GPC technology. Its application allows the development of relevant graphs to quickly identify the most critical malfunctions.