Different mixture experiment analysis results JMP 17 & 18

[#1]

Did something in JMP 18 change in analysis of mixture experiment results. Below is shown that analysis results from exactly the same DOE data sets are different

1. DOE three component mixture

JMP 17 results 

JMP 18 Results

2. DOE three mixture components + one process effect

JMP 17 results 

JMP 18 results 

In JMP 18 analysis above the model is different!

What has changed and why? Remark: despite of different plots & model graphs of JMP 17 - 18 prediction profilers are identical. 

[#2]

I'm not sure the correct word is accurate...different, yes.  It appears the JMP18 version looks more like a leverage plot than the one from JMP17.  Typically those plots are narrowest in the center and expand near the ends.  Collinearity is typically a cluster of points near the middle.

https://www.jmp.com/support/help/en/18.1/#page/jmp/effect-leverage-plots.shtml?os=mac&source=applica...

[#3]

The DOE analysis script is 100% reproducible both in JMP 17 and 18.  When running second DOE (mixture + process effect) analysis script, developed in jmp 17, in jmp 18 besides the prediction plot also model is different (?) The prediction profilers always are equal.

[#4]

I'm confused.  I posted the output models for both 17 and 18 above.  They are identical.  The only difference is the leverage plot. You must have some preferences set differently in the 2 versions.

[#5]

Yes, but in your initial post, the statistics were different as well. That does not appear to be a JMP issue.

[#6]

As in case 1 the case 2 data set and analysis script are exactly the same, indeed now results are also different..

Only difference is the two jmp versions

[#7]

Hi @frankderuyck,

I might have found a clue about the difference in plots.

• In JMP 17, when you extend the ranges of "Actual by Predicted" plot, it seems the plot is constructed by using a response mean of 0 (confidence band is symetrical around 0):
  
  So maybe the modeling without intercept of mixture models was (incorrectly ?) translated into a modeling with intercept = 0, hence the confidence band being large and non-symetrical around the response mean.
• In JMP 18, you don't observe this situation as confidence band are symetrical around the response mean (5,88) :
  

Curious to know if any developers might confirm or inform about this difference in plots. @Ryan_Lekivetz ?

Best,

[#8]

Hi @frankderuyck ,

For any question like this I would recommend to contact JMP Technical Support (support@jmp.com). Send example data with saved scripts so they can most easily recreate the analysis exactly as you have done it. They will also need information about the version(s) of JMP that you are using.

Regards,

Phil

[#9]

OK Phil, I informed technical support about this discussion

[#10]

Tech support will certainly get to the bottom of this. However, I do believe that @Victor_G  might be on to something. I ALWAYS suggest to people fitting mixture models to look at the overall ANOVA report (Regression Reports > Analysis of Variance). It is closed by default , but I wish it were open and visible for your analyses.

If you are fitting a mixture model, that report will have the message: Tested against reduced model Y=mean. This is what you SHOULD see when fitting a Scheffe mixture model.

If it is a no-intercept model, the report will have the message: Tested against reduced model Y=0.  We do NOT want this for a Scheffe mixture model. This might occur if the mixture components do not always add to exactly 1 or perhaps some of the components do not have the correct column properties assigned.

Again, I know tech support will get to the correct answer, but I wanted to chime in on this item that is often overlooked when fitting a Scheffe mixture model.

[#11]

Agreed, I think Victor figured it out.  The JMP 18 leverage plots look "more correct" IMHO.