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Gage R&R: Nested vs Crossed vs Nested Then Crossed vs Crossed then Nested

Hi,

 

I am running a Gage R&R study with 2 factors (Operator and Location), 3 different parts and 3 repetition per part. Operator and Location are nested. This means each location has 2 different operators but the parts are the same. This mean that parts has been moved from one location to the other to be tested by different operators. What option should I use? I would say it is nested then crossed since operator and location are nested but sample and operator with location is crossed. Am I right?

Advanced Statistical ModelingQuality and Process EngineeringRe: Gage R&R: Nested vs Crossed vs Nested Then Crossed vs Crossed then Nested

Please see the documentation about launching this platform in case your question is about which analysis role should be used with your variables.

Re: Gage R&R: Nested vs Crossed vs Nested Then Crossed vs Crossed then NestedHi,

Thanks for the response. I have a question/concern about introducing factors. What would be the difference between your proposal and the scenario of only declaring as factor Location and Operator and inserting Sample/Part variable under Sample box while designing the gauge r&r experiment and selecting nested as gauge option? They should be the same right?

Thanks again

JuanRe: Gage R&R: Nested vs Crossed vs Nested Then Crossed vs Crossed then Nested

First welcome to the community.  You are correct, Operator is nested in Location, Operator and parts are crossed and measurements are nested in Op/Parts.

 

Re: Gage R&R: Nested vs Crossed vs Nested Then Crossed vs Crossed then Nested

I think if you enter the factors in this order, Location > Operator > Part, then the Nested and Crossed option should be valid.

Re: Gage R&R: Nested vs Crossed vs Nested Then Crossed vs Crossed then Nested

Hi @jp2,

Concerning your problem, I would also have the same response as you have : your problem seems to involve nested then crossed factors.
One option to see which model type sounds reasonable is to launch the Variability Chart platform, and continue the Gage R&R analysis in the two possible models: Nested then Crossed or Crossed then Nested (full crossed or full nested won't be of interest here), and look at which interactions are present in the Gauge R&R panel (see images).

You can see that interactions present in the Nested+Crossed do correspond to what you can effectively measure : Part x Operator and Location x Part (since all combinations are done for these two interaction terms).
In the Crossed+Nested model, the interaction Operator x Location is mentioned, but is in fact not fully estimable, since not every operator will face the two possible locations.

You can have a look and test these options (scripts saved) with the test dataset I created for your case.

Hope this help you,