Which quality control tool is commonly used to monitor process variability?

Control charts are a fundamental quality control tool designed specifically for monitoring process variability over time. They provide a visual representation of data points collected from a process, allowing users to observe trends, fluctuations, and patterns that indicate whether the process is operating within specified control limits.

These limits are determined based on statistical calculations and help identify any variations that may signal a potential issue. By displaying data points along with control limits on a time scale, control charts enable practitioners to quickly assess the stability and capability of a process. If the data points remain within the control limits, it indicates that the process is in control; if they fall outside, it can suggest that corrective action may be necessary.

In contrast, flow charts are used to illustrate the steps in a process, scatter plots help identify relationships between two variables, and histograms provide a graphical representation of the distribution of numerical data. While these tools have their own specific uses in quality management, control charts are uniquely positioned to focus on monitoring process variability effectively.