GR&R Studies: Measuring the Measurement  Over the last few
columns we’ve been talking about measurement system analysis, or
MSA. A key component of this overall analytical process is the
GR&R study, officially known as ANOVA GR&R, or “Analysis of
Variance Gage Repeatability and Reproducibility.”  Columns From:
8/18/2010 Modern Machine Shop,  Click Image to Enlarge  The
purpose of a GR&R study is to measure the variability induced in
measurements by the gage or measuring system, and then compare
it to the total variability allowed by the part tolerance to
determine if the measuring system is adequate for the task. We
all know that the measuring system is more than just the gage.
From our SWIPE discussions we know the whole process consists of
the Standard (master), the Workpiece, the Instrument (gage), the
People and the Environment. Besides these key components, a GR&R
study also takes into account: • The test method. How the gage
is set up, the instructions for using the gage and how data is
to be collected.