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Gage R&R

Blog posts and articles about Gage Repeatability and Reprodicibility (Gage R&R) studies for quality improvement.

Last week, a customer called with an issue related to running a Gage R&R nested design in Minitab Statistical Software.  Everything initially looked okay, as he had the three columns necessary to perform a successful study: one for parts, one for operators, and another for the measurements.  However, when he tried to analyze his data using Stat > Quality Tools > Gage Study > Gage R&R (Nested), he... Continue Reading
When I first started learning about Lean Six Sigma and familiarizing myself with all the different terminology and methodologies, I was a little overwhelmed and confused by all the acronyms. FMEA, C&E Matrix, Gage R&R, SIPOC, DMAIC…the list goes on and on! However, I really got tripped up by the similar-sounding acronyms of DMAIC, DMADV, and DFSS. These acronyms stand for the most common Lean Six... Continue Reading
In recent posts, we’ve reviewed a number of Measurement Systems Analysis (MSA) studies: Type I Gage Studies, Linearity and Bias Studies, and Gage R&R Studies. Before that, we took a look at a cause and effect diagram, also called a fishbone diagram. And we did all this because we were getting ready to practice a designed experiment.   Remember the fishbone diagram?   On the fishbone diagram, I... Continue Reading
So this time, we finally have the fun of getting to look at the full gage R&R results. Here’s how the data turned out, and some of the exciting stuff that went along with getting it.   RunOrder Operators Parts Measurements 1 J1 Red 37.9375 2 J1 Green 28.375 3 J1 Yellow 72.25 4 J2 Yellow 72.0625 5 J2 Red 38.25 6 J2 Green 28.4375 7 Kevin Red 41.0625 8 Kevin Green 22.25 9 Kevin Yellow 72.1875 10 J3 Green 22.1875 11 J3 Yellow 72.3125 12 J3 Red 40.9375 13... Continue Reading
Now that we’ve explored using gummi bears to do a gage Linearity and Bias Study and a Type I Gage Study, it’s time to use gummi bears to practice the third and final type of measurement systems analysis that I’m planning to demonstrate: the gage R&R study."R&R" stands for Repeatability and Reproducibility, which are the two sources of variation we typically evaluate in a gage R&R study.... Continue Reading
Last time, we set up a worksheet for doing a Gage Linearity and Bias Study in Minitab Statistical Software. This time, we’ll take a look at my sample data and see what we might learn from a Gage Linearity and Bias Study. Getting comfortable with the variation present in measurement systems will go a long way towards building your confidence with quality statistics. Remember too that the... Continue Reading
Today, we’re going to get ready to do a Gage Linearity and Bias Study with gummi bears. But to do the linearity and bias study, you first have to talk more about how to collect the data. The Gage Linearity and Bias study has a complication that wasn’t present in the Type 1 Gage Study.The point of the gage linearity and bias study is to assess the bias of a gage across its operating range, not just... Continue Reading
Gummi bears have more to teach us about measurement systems analysis.Today, we’ll look at doing a Type 1 Gage Study, which compares the measurement variation to the specifications for your process, to judge whether a gage is measuring well enough. The Type 1 Gage Study is a starting point because it evaluates accuracy, precision, and consistency, but only for a single case. Later, we’ll look... Continue Reading
What can gummi bears tell us about measurement system analysis?  We're still practicing statistics with gummi bears, because they don't bounce or slide off of popsicle sticks. In my last post, we looked at some factors that might affect how far a gummi bear flies off of a popsicle stick catapult. Next, what we'd really like to do is to pick some factors to study and do a designed experiment to... Continue Reading
Another common question with Gage Crossed is what table to look at when assessing your measurement system.  By default, Minitab gives a %Contribution table and %Study Variation table. Which one should you use when assessing where the variation is mostly coming from? Well, you could use either of them.The %Contribution table can be convenient because all sources of variability add up nicely to... Continue Reading
Recently I've been thinking about common questions that customers ask when running a Gage R&R analysis in Minitab. For example, when you run a Gage R&R, the last result that shows up in the session window is a value for the ‘Number of Distinct Categories’.  This one metric is something that customers seem to overlook when they call to discuss their Gage studies.          This value represents the... Continue Reading
“Fear leads to anger, anger leads to hate, hate leads to suffering.” Yoda This quotation sums up the way most people’s relationship to statistics develops. But not me. My name is Cody Steele, and I’m the guy who Eston Martz warned you about. From the time my 6-year-old self decided that Superman’s most amazing power was his intelligence, through buying a calculus book after college so that I could... Continue Reading
Data collection involves taking measurements, and this seems like a simple thing when the subject is relatively simple.  However, even the simplest of cases has the potential to be messed up.  I found this out the hard way once. I hope sharing it helps you avoid a similar experience. Experienced researchers and quality practitioners know they need to verify that a measurement system provides valid... Continue Reading