Average and mean charts should not be read as a control chart. The data is plotted by sample number and not time sequence. Each chart plots the mean of each sample part and the range of each sample part by operator. In the example, one can tell that all operators have similar averages on all 10 parts; however, the second operator, Justin Thom, has much more variation on each part. The next step here would be to determine if Justin is following the correct procedures or if he has been properly trained.
Understanding how to properly conduct a gauge R&R study and how to interpret the results is a key skill for quality professionals. For more detailed information, consult AIAG's Measurement Systems Analysis, third edition, 2002, and Evaluating the Measurement Process, Wheeler and Lyday, 1984.
This series of blogs will include:
- What does it measure?
- Conducting a Study
- Evaluating the Gauge Study: The TV Report
- Evaluating the Gauge Study: The TT Report