Stability of a gage is defined as error (measured in terms of Standard Deviation) as a function of time. Environmental conditions such as cleanliness, noise, vibration, lighting, chemical, wear and tear or other factors usually influence gage instability. Ideally, gages can be maintained to give a high degree of Stability but can never be eliminated unlike Reproducibility. Gage Stability studies would be the first exercise after calibration procedures.

Control Charts are commonly used to track the Stability of a measurement system over time.