What is the main function of a control chart?

The main function of a control chart is to monitor process stability and variation over time. Control charts are statistical tools used in quality control that help organizations visualize how a process behaves in terms of variation and to identify any trends or shifts in performance. By plotting data points over time, control charts allow practitioners to establish control limits based on historical data, indicating the expected range of variation for a given process. When data points fall outside these control limits, it signals that the process may be affected by special causes of variation, indicating a need for investigation or intervention.

In contrast, tracking marketing trends, monitoring employee performance, and analyzing customer feedback focus on different aspects of organizational performance rather than on process variation and control. These functions may contribute to overall quality management but do not directly utilize control charts as a primary analytical tool. Thus, the function of a control chart is specifically oriented towards understanding and maintaining process stability and variation.