From the LEAN SIX SIGMA POCKET
(Michael L. George, David Rowlands, Mark Price, John Maxey)
Purpose
To Determine if a measurement system can generate accurate data, and if the accuracy is adequate to achieve your objectives.
Why Use MSA
Types of MSA
Gage R&R
Bias Analysis
Stability Analysis
Discrimination Analysis
Kappa Analysis
Components of measurement error
Measurements need to be "precise" and "accurate". Accuracy and precision are different, independent properties :
(Michael L. George, David Rowlands, Mark Price, John Maxey)
Purpose
To Determine if a measurement system can generate accurate data, and if the accuracy is adequate to achieve your objectives.
Why Use MSA
- To Make sure that the differences in the data are due to actual differences in what is being measured and not to variation in measurement methods
- Note : Experience shows that 30% to 50% of measurement systems are not capable of accurately or precisely measuring the desired metric
Types of MSA
Gage R&R
Bias Analysis
Stability Analysis
Discrimination Analysis
Kappa Analysis
Components of measurement error
Measurements need to be "precise" and "accurate". Accuracy and precision are different, independent properties :
- Data may be accurate (Reflect the true values of the property) but not precise (measurement units do not have enough discriminatory power)
- Vice versa, data can be precise yet inaccurate (they are precisely measuring something that does not reflect the true values)
- Sometimes data can be neither accurate not precise
- Obviously, the goal is to have data that are both precise and accurate.
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