What type of chart is used primarily to assess the ongoing performance of a process?

A control chart is used primarily to assess the ongoing performance of a process by monitoring its variability over time. Control charts help determine whether a process is stable and predictable by displaying data points in relation to control limits. These limits represent the expected range of variation due to common causes in the process. If data points fall outside these limits or show non-random patterns, it indicates that there may be special causes needing investigation.

Control charts are essential for managing and improving quality in processes, enabling teams to quickly identify trends or shifts that could negatively impact performance, thereby allowing for timely corrective actions. This focus on continuous monitoring sets control charts apart from other types of charts like histograms, which summarize data distribution at a specific moment, fishbone diagrams, which are used for root cause analysis, and Gantt charts, which are utilized for project scheduling and tracking timelines.