Measurement System Analysis (MSA) Flashcards

What is 'resolution' (also called 'discrimination') in a measurement instrument?

Answer: The smallest detectable increment or unit the instrument can read

Resolution is the smallest increment that a measurement instrument can detect and display; insufficient resolution prevents the instrument from distinguishing small differences between parts.

A rule of thumb in MSA states that an instrument's resolution should be no greater than what fraction of the process variation or tolerance?

Answer: 1/10

The AIAG MSA Reference Manual recommends that the measurement increment (resolution) should be no larger than one-tenth (1/10) of the process variation or tolerance to avoid masking real differences.

If a Gauge R&R study shows a high %GRR (e.g., 45%), which corrective action is most directly appropriate?

Answer: Investigate and reduce sources of measurement variation such as gauge wear, operator technique, or fixturing

A high %GRR means the measurement system contributes excessive variation; the corrective path is to identify and eliminate the root causes — gauge condition, operator method, environmental factors, or fixturing — not to change specifications or sampling.

What does 'reproducibility' measure in a Gauge R&R study?

Answer: The variation in average measurements produced by different operators using the same gauge on the same parts

Reproducibility (Appraiser Variation) quantifies how much the measurement average changes when different operators use the same instrument to measure the same parts.

In Attribute MSA, a 'miss rate' (false negative) occurs when:

Answer: An operator accepts a part that is actually defective

A miss (false negative / Type II error) occurs when the measurement system or appraiser incorrectly accepts a nonconforming part, allowing a defect to pass through uninspected.

Which of the following best describes a 'false alarm rate' (Type I error) in Attribute MSA?

Answer: Rejecting a conforming (good) part as though it were defective

A false alarm (Type I error) occurs when the measurement system incorrectly rejects a conforming part, causing unnecessary scrap, rework, or customer disputes.

What is the minimum recommended number of parts (samples) for a standard crossed Gauge R&R study per AIAG guidelines?

Answer: 10 parts, 3 operators, 2 replicates

The AIAG MSA Reference Manual recommends a minimum study of 10 parts, 3 operators, and 2 replicates (60 total measurements) to provide statistically meaningful estimates of repeatability and reproducibility.