Rabu, 22 Oktober 2008

MSA (Measurement System And Analysis)

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
  • 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.

Information From

Tidak ada komentar: