An artifact or instrument measured periodically, often alongside customer work, so its results can be plotted on a control chart. As long as the readings stay inside the control limits, the lab has evidence that the measurement system has not drifted or broken between calibrations. Its history also yields a long-term standard deviation that makes a realistic Type A input to the uncertainty budget.
Check standard went past the upper control limit this morning, stop and find out why before running any more gauges.
A check standard does not need a calibration of its own to do its job; it only needs to be stable, because you are watching for change.
Also heard as
- control standard
- check artifact
Related terms
Working standard
A standard used routinely to calibrate instruments, itself checked against the lab's reference standard.
Stability
The ability of an instrument or standard to hold its calibrated values as the weeks and months pass.
Intermediate precision
Precision measured within one lab over longer periods, with changes such as different days, operators or recalibrations.
Bias
The estimated systematic offset of a measuring system: its average reading minus the reference value.
Drift
Gradual change in an instrument's readings over time that comes from the instrument itself, not from what it measures.