The scatter that shows up when one person repeats the same measurement on the same item, with the same setup and in the same place, within one short session. It is expressed as the standard deviation of those replicates and enters most budgets as a Type A component. Repeatability is the smallest scatter a method will ever show, since it leaves out day-to-day and person-to-person effects.
Repeatability on the bore gauge is 0.4 microns over ten readings, so scatter isn't the problem.
Also heard as
- short-term precision
Do not mix it up with
- Reproducibility: Reproducibility deliberately changes operators, labs or equipment; repeatability holds them all fixed.
Related terms
Reproducibility
How well results on the same item agree when the lab, operator, equipment or day is changed on purpose.
Intermediate precision
Precision measured within one lab over longer periods, with changes such as different days, operators or recalibrations.
Precision
How well repeat readings of the same item agree with one another, with no reference to whether they are right.
Type A evaluation
Putting a number on an uncertainty component by running statistics on your own repeat readings.
Standard deviation
The usual measure of scatter in a set of values, the square root of the average squared deviation from the mean.