Define & Measure (MSA)

In a Measurement System Analysis, what does 'repeatability' specifically measure?

• AThe variation obtained when the same operator measures the same part repeatedly with the same gauge✓
• BThe difference between the gauge's average reading and a known reference value
• CThe change in gauge bias across the operating range of the instrument
• DThe variation between different operators measuring the same part

Answer: Repeatability (equipment variation) is the variation seen when one operator measures the same part multiple times with the same gauge under identical conditions.

In a Gage R&R study, 'reproducibility' refers to which source of variation?

• AVariation in the true values of the parts being measured, properly called part-to-part variation
• BVariation in measurements caused by differences between operators (appraisers)✓
• CDrift in the measurement system over an extended period of time, known as gauge stability
• DVariation from one appraiser repeating a measurement on the same part with the same gauge

Answer: Reproducibility (appraiser variation) is the variation in the average of measurements made by different operators using the same gauge on the same parts.

Using AIAG guidelines, a Gage R&R result expressed as % study variation of 8% indicates a measurement system that is:

• AAcceptable for use✓
• BAcceptable for sorting parts, but not for process control
• CUnacceptable, needing a new gauge
• DMarginal, acceptable depending on the application

Answer: AIAG guidelines classify %GRR below 10% as acceptable, 10-30% as marginal (conditionally acceptable), and above 30% as unacceptable.