SPC Measurement System Analysis (MSA) 1 — Questions and Answers
Question 1: What does 'Gauge R&R' stand for in Measurement System Analysis?
- Gauge Repeatability and Reproducibility (Correct answer)
- Gauge Reliability and Repeatability
- Gauge Range and Resolution
- Gauge Ratio and Regression
Correct answer: Gauge Repeatability and Reproducibility
Gauge R&R stands for Gauge Repeatability and Reproducibility, the two main components of measurement variation studied in MSA.
Question 2: What is the primary purpose of conducting a Measurement System Analysis (MSA)?
- To reduce the number of gauges used in production
- To determine whether a measurement system is capable of producing reliable data (Correct answer)
- To calibrate instruments to NIST standards
- To identify which operators need additional training
Correct answer: To determine whether a measurement system is capable of producing reliable data
MSA determines whether the measurement system contributes acceptable levels of variation relative to the process or specification, ensuring data reliability for decision-making.
Question 3: In a Gauge R&R study, 'repeatability' refers to variation from which source?
- Different operators measuring the same part
- Different gauges measuring the same part
- The same operator measuring the same part multiple times (Correct answer)
- Different parts measured by the same operator
Correct answer: The same operator measuring the same part multiple times
Repeatability (Equipment Variation) is the variation observed when the same operator measures the same part multiple times with the same gauge under the same conditions.
Question 4: According to AIAG guidelines, a Gauge R&R %Study Variation below what threshold is generally considered acceptable?
- 5%
- 10% (Correct answer)
- 20%
- 30%
Correct answer: 10%
Per AIAG MSA guidelines, a %Study Variation below 10% is acceptable; 10–30% may be acceptable depending on circumstances; above 30% the measurement system needs improvement.
Question 5: Which MSA characteristic measures the difference between the observed average measurement and the true (reference) value?
- Linearity
- Stability
- Bias (Correct answer)
- Reproducibility
Correct answer: Bias
Bias (also called accuracy) is the difference between the observed average measurement and the reference or true value of a part.
Question 6: What does 'linearity' describe in the context of a measurement system?
- The consistency of measurements taken in a straight-line pattern across the shop floor
- The change in bias across the operating range of the measurement instrument (Correct answer)
- The correlation between two different measurement instruments
- The ability of the gauge to measure parts in a linear sequence
Correct answer: The change in bias across the operating range of the measurement instrument
Linearity assesses whether the bias of a measurement system is consistent (or changes) across the full range of expected measurements.
Question 7: In MSA, 'stability' (or 'drift') refers to which measurement system property?
- The ability of the gauge to measure parts of different shapes
- The variation in bias of a measurement system over time (Correct answer)
- The consistency of measurements across different locations
- The operator's ability to hold the gauge steady
Correct answer: The variation in bias of a measurement system over time
Stability measures how much the bias of a measurement system changes over time when measuring the same reference standard under the same conditions.
SPC Measurement System Analysis (MSA) 1
What does 'Gauge R&R' stand for in Measurement System Analysis?