What is the purpose of a control chart?

The purpose of a control chart is to monitor process behavior over time. Control charts are statistical tools used in quality control to determine if a process is stable and performing predictably. By plotting data points of a process over time, variations caused by common causes (natural variations inherent in the process) and special causes (unexpected variations) can be distinguished.

When a control chart is used, it typically shows upper and lower control limits, which help identify trends or shifts in the process that may require investigation or corrective action. This monitoring allows organizations to maintain control over their processes, seek continuous improvement, and ensure that the process remains within specified limits, thereby maintaining quality standards.

In contrast, the other options serve different purposes; for example, illustrating project budgets and documenting project milestones do not provide insights into process variability and stability as control charts do. Evaluating team performance is a separate area focused on human resources and productivity rather than the statistical analysis of process quality. Thus, option B accurately captures the fundamental role of control charts in Six Sigma methodology.