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Alicia
Level III

EMP Gauge R&R - Reproducibility = 0%

Hi there!

 

I've ran EMP Gauge R&R and the results show the total variation coming from reproducibility is 0%. However, when I look at the data there are considerable differences in the measured variable of the same samples between operators so I can't understand how the reproducibility variation is 0%:

 

Capture.PNG

 

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Can anyone help please?

 

Thank you in advance,

 

Alicia

 

 

 

1 ACCEPTED SOLUTION

Accepted Solutions
statman
Super User

Re: EMP Gauge R&R - Reproducibility = 0%

First I added a column and called it measurement to represent the repeatability component of measurement precision (consecutive numbers 1-60). Then I analyzed your data using the JMP EMP (under Measurement System Analysis) and using Variability charts/control charts (attached document summarizes analysis).  To be honest, I don't know why the EMP platform gives 0% reproducibility other than the operator component is so small, perhaps it rounded it to 0? Perhaps a JMP representative can explain this? I suppose I'm old fashioned, but I do the analysis per Don Wheeler's recommendations, something I learned from him many years ago.  See Wheeler & Lyday:  "Evaluating the Measurement Process".

"All models are wrong, some are useful" G.E.P. Box

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9 REPLIES 9
Mauro_Gerber
Level IV

Re: EMP Gauge R&R - Reproducibility = 0%

Hello Alicia
Can you please make a print screen of the input mask from the EMP platform?

 

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Alicia
Level III

Re: EMP Gauge R&R - Reproducibility = 0%

Hello Mauro,

 

Is this what you wanted to look at?

 

Capture.PNG

 

Best regards,

 

Alicia

statman
Super User

Re: EMP Gauge R&R - Reproducibility = 0%

You need both operator and sample in the X grouping.  Could you attach your data set?  Did you do repeated measures for each sample/operator?  How would you estimate precision repeatability without that?  In which case you will have operator and sample crossed and repeated measures nested.

"All models are wrong, some are useful" G.E.P. Box
Alicia
Level III

Re: EMP Gauge R&R - Reproducibility = 0%

Hi, please see data attached. Yes repeated measures was used - each operator A, B and C tested samples 1 - 10 twice. Thanks for your help in advance

statman
Super User

Re: EMP Gauge R&R - Reproducibility = 0%

First I added a column and called it measurement to represent the repeatability component of measurement precision (consecutive numbers 1-60). Then I analyzed your data using the JMP EMP (under Measurement System Analysis) and using Variability charts/control charts (attached document summarizes analysis).  To be honest, I don't know why the EMP platform gives 0% reproducibility other than the operator component is so small, perhaps it rounded it to 0? Perhaps a JMP representative can explain this? I suppose I'm old fashioned, but I do the analysis per Don Wheeler's recommendations, something I learned from him many years ago.  See Wheeler & Lyday:  "Evaluating the Measurement Process".

"All models are wrong, some are useful" G.E.P. Box
Alicia
Level III

Re: EMP Gauge R&R - Reproducibility = 0%

Thank you so much for the helpful replies! This makes sense to me now. Really appreciated!

Re: EMP Gauge R&R - Reproducibility = 0%

The Operator variance component is negative and has therefore been set to 0.  You can see this via Fit Model.  

 

Fit Model(
	Y( :Impact Strength ),
	Effects,
	Random Effects( :Sample, :Operator, :Sample * :Operator ),
	NoBounds( 1 ),
	Personality( "Standard Least Squares" ),
	Method( "REML" ),
	Emphasis( "Minimal Report" ),
	Run(
		:Impact Strength << {Summary of Fit( 1 ), Analysis of Variance( 0 ), Parameter Estimates( 1 ),
		Scaled Estimates( 0 ), Plot Actual by Predicted( 0 ), Plot Regression( 0 ),
		Plot Residual by Predicted( 0 ), Plot Studentized Residuals( 0 ), Plot Effect Leverage( 0 ),
		Plot Residual by Normal Quantiles( 0 )}
	)
);

 

The reproducibility value given in the EMP Gauge R&R Results report does not include interactions and negative variance components are set to zero.

statman
Super User

Re: EMP Gauge R&R - Reproducibility = 0%

OK, that makes sense.  Negative REML...That is why JMP switched to Bayesian estimates...

"All models are wrong, some are useful" G.E.P. Box
Alicia
Level III

Re: EMP Gauge R&R - Reproducibility = 0%

Many thanks for the script... really helpful!