ndc

number of distinct categories

ndc = 1.41 · σ_part / σ_GRR

How many groups of parts the measurement system can reliably tell apart within the part variation of the study. AIAG requires ndc ≥ 5. An ndc of 1 means the gauge cannot distinguish the parts at all.

Calculate it

Gage R&R (MSA): Crossed study with ANOVA: repeatability, reproducibility, %GRR, % tolerance and ndc.

Related terms

• %GRR: gauge repeatability and reproducibility