The control chart is a graph used to study how a process changes
over time. Data are plotted in time order .
When to Use a Control Chart
- When controlling ongoing processes by finding and correcting
problems as they occur.
- When predicting the expected range of outcomes from a
process.
- When determining whether a process is stable (in statistical
control).
- When analyzing patterns of process variation from special
causes (non-routine events) or common causes (built into the
process).
- When determining whether your quality improvement project
should aim to prevent specific problems or to make fundamental
changes to the process.