Precision
Closeness of measurements to each other — small spread, regardless of position relative to the reference value.
Also known as: measurement precision, measurement dispersion
Precision is a pure dispersion property describing how tightly repeated measurements cluster. It is the second half of accuracy — parallel to trueness, which addresses position.
The usual metric is the standard deviation of repeated measurements. ISO 5725 grades precision by which conditions are held constant between measurements:
- Repeatability — tightest conditions: same operator, same instrument, same part, short time
- Reproducibility — changed conditions: different operators, instruments, or laboratories
- Intermediate precision: individual factors varied (e.g. day, batch, calibration)
See also
Used in
In the Algorithm Lab
Sources
- DIN ISO 5725-1/-2: Genauigkeit (Richtigkeit und Präzision) von Messverfahren und Messergebnissen
- VDA Band 5 — Prüfprozesseignung, 3. Auflage
- AIAG — Measurement Systems Analysis Reference Manual, 4th Edition (MSA-4)