Special Cause Variation
Quality
Special Cause Variation
Variation caused by a specific, identifiable factor outside the normal behavior of a stable process.
Examples
- 01The bore size jumps by 0.03 mm right after a tool change, a clear case of special cause variation.
- 02In the supplier review, every special cause variation signal on the control charts must be explained with a cause and a recorded action.
- 03Once the special cause variation is traced to a loose tool holder, a torque check for the holder is added to the setup sheet.