Cgk (Repeatability and Bias Index)
MSA Type 1 metric combining repeatability and bias in a single figure.
Also known as: repeatability and bias index, Cgk value
The Cgk index extends Cg to include the instrument's systematic deviation from the reference value. It thus covers both precision and trueness in a single number.
Half the allowed tolerance fraction is reduced by the absolute bias and divided by the weighted spread. It always holds — the gap shows how much capacity the bias "consumes".
See also
Used in
In the Algorithm Lab
Sources
- VDA Band 5 — Prüfprozesseignung, 3. Auflage
- AIAG — Measurement Systems Analysis Reference Manual, 4th Edition (MSA-4)
- Dietrich, E. & Schulze, A. — Statistische Verfahren zur Maschinen- und Prozessqualifikation, 7. Auflage, Hanser