Abstract: The statistical process control (SPC) subsystem is the heart of the data collection and process control system for semiconductor manufacturing in the various embodiments as disclosed herein. SPC is responsible for performing calculations to generate statistics on collected measurement data, applying rules to the statistics, and executing error actions when those rules are violated. SPC subsystem plays a role in corrective actions as well by lifting restrictions previously imposed on tools or lots as a result of rule violations. In an embodiment, SPC is supported through underlying transaction and performance monitoring system components. In an embodiment, SPC procedure is a statistical engine that performs what the process control strategy (PCS) describes, hence there is at least one SPC procedure for each PCS. Components in SPC send data to the chart client subsystem as embodied herein, which allows visualization of statistics generated by SPC procedure in graphical chart form via a web browser.