What tool displays performance outside of expected values to merit a deeper analysis?

A control chart, also known as a Shewhart chart or process-behavior chart, is a statistical tool used to monitor how a process changes over time. It helps distinguish between common causevariations (natural fluctuations inherent to the process) and special cause variations (unexpected fluctuations due to specific factors). By plotting data points in time order and establishing upper and lower control limits, control charts enable quality professionals to identify when a process is operating outside of its expected parameters, signaling the need for further investigation.

In contrast, a bar chart is a graphical representation of categorical data with rectangular bars, a Pareto chart is a type of bar chart that identifies the most significant factors in a dataset, and a run chart displays data points over time without control limits. While these tools are useful for various purposes, they do not provide the same level of insight into process stability and variation as control charts.