What is the purpose of a control chart in quality management?

A control chart serves primarily to track process performance over time by representing data points related to a specific quality characteristic and plotting them within a time series. The chart helps in identifying variations within processes, categorizing them as either common cause variation (inherent to the process) or special cause variation (indicative of an anomaly). This tracking is vital as it allows teams to monitor the stability and capability of a process, leading to informed decision-making on when improvements may be necessary.

While summarizing data, displaying trends, and calculating mean values are all important tasks in quality management, they do not encapsulate the primary function of a control chart as effectively as tracking process performance does. A control chart facilitates continuous improvement initiatives by providing real-time feedback on process capabilities and identifying when corrective actions are needed.