In a measurement assurance program, data from what unit will be plotted on a control chart?

In a measurement assurance program, the correct unit for plotting data on a control chart is the check standard. The purpose of a control chart is to monitor the consistency and stability of a measurement process over time. Check standards are used specifically for this purpose as they provide a reliable reference point against which the measurement system can be evaluated. They are routinely measured to ensure that the calibration and measurement processes remain in control and that any variations can be detected early.

Using check standards for control charts allows for ongoing verification of measurement accuracy, ensuring that the calibration procedures are effective and that the measuring equipment is functioning correctly. In contrast, test samples may not provide consistent results due to their inherent variability, while calibration standards serve as the benchmarks for calibration but do not assess ongoing performance. Historical data archives can be useful for reference but do not provide the real-time monitoring necessary for a control chart.

Overall, the use of check standards in a control chart effectively supports the goal of maintaining measurement reliability and quality in a measurement assurance program.