Measurement System Analysis and Gage R&R Flashcards

What does MSA stand for in the context of Lean Six Sigma?

Answer: Measurement System Analysis

MSA stands for Measurement System Analysis, a structured study that evaluates the accuracy and precision of a measurement system.

Which two components of variation does a Gage R&R study measure?

Answer: Repeatability and Reproducibility

Gage R&R measures Repeatability (variation from the same operator and gage on the same part) and Reproducibility (variation between different operators).

Repeatability in a Gage R&R study is defined as the variation observed when:

Answer: The same operator measures the same part multiple times with the same gage

Repeatability captures equipment variation — it is the variation seen when one operator repeatedly measures the same part with the same gage.

What is the primary purpose of conducting a Gage R&R study in the Measure phase?

Answer: To determine whether the measurement system can detect real process variation

Gage R&R determines whether measurement system error is small enough relative to process variation to allow valid data collection and analysis.

What %Gage R&R value is generally considered acceptable according to AIAG guidelines?

Answer: Less than 10%

A measurement system with %Gage R&R below 10% is considered acceptable, meaning measurement error is a small fraction of total observed variation.

Which metric in Gage R&R indicates how many distinct groups a measurement system can reliably differentiate?

Answer: Number of Distinct Categories (NDC)

The Number of Distinct Categories (NDC) indicates how many separate groups the measurement system can reliably discriminate; an NDC of 5 or more is generally required.

Bias in a measurement system is best defined as:

Answer: The difference between the observed average measurement and the known reference (true) value

Bias is the systematic offset between the average measured value and the true reference value, indicating a consistent over- or under-reading.