Which method is typically used to ensure a process stays within control limits?

Statistical process control (SPC) is the method used to monitor and control a process by using statistical techniques. By establishing control limits based on statistical analysis of process data, SPC helps to ensure that the process remains stable and predictable over time. It involves collecting data at regular intervals and plotting this data on control charts to visually assess whether the process variations are within acceptable limits. If the process data points fall within these control limits, it indicates that the process is in control; if they fall outside, this signals a potential problem that requires further investigation.

Other methods, while valuable in quality management, do not specifically focus on monitoring ongoing processes. Benchmarking involves comparing processes with industry standards or best practices to identify areas for improvement, but it does not provide ongoing control of processes. Root cause analysis is used to identify the underlying causes of specific problems or failures after they have occurred, and quality circle discussions are more about collective problem-solving and employee involvement rather than providing continuous control over a process. Therefore, the focus and application of statistical process control make it the appropriate choice for ensuring that a process stays within control limits.