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DoE: disallowed combinations filter gives unexpected result

Hi there,

 

I'm making a testplan for a multilaboratory study on mechanical properties of steel. One of the parameters of interest is "surface roughness" which can have three values (-1,0,1). However for technical reasons the highes surface roughness can only be applied to samples with a minimum diameter of 6 mm. To take that into account, I use the disallowed  combinations filter :

Diameter >= 0 & Diameter <= 5.625 & (Surface roughness >= 0.4306 & Surface roughness <= 1)

This should preclude any tests where the specimen diameter is below 5.625 and the surface roughness above 0.4306. (The decimal number come from using the sliders. There are only a limited number of diameters and 3 surface roughness values, so the excat numbers don't matter.)

 

Nevertheless the test plan comes up with a test (#32 in the attached file) with surface roughness 1 for a diamter of 4.5. (Which according to my understanding should be excluded.)

 

Do I misunderstand something?

 

I attach the Jmp script for reference. (I normally don't use scripting, I just saved the script for this post.)

 

1 ACCEPTED SOLUTION

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Re: DoE: disallowed combinations filter gives unexpected result

Apologies that you came across this issue. You are correct in your understanding - unfortunately, this is an issue that can sometimes occur with covariates and disallowed combinations. For this particular example, I would manually change surface roughness to a valid value (I think either choice shouldn't make a big difference, but if you're concerned, you can try Evaluate Design or Compare Designs to check).

 

I've made a note to get this addressed for a future release.


Cheers,

Ryan

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5 REPLIES 5
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Re: DoE: disallowed combinations filter gives unexpected result

Hello;

 

The session script that you attached contains only a link to the table on your system, but not the table itself:

"N:\G.I.4\03_INCEFA+\05_technical\test_matrix\02_phase2\Custom DesignPhase_II.jmp"

 

Could you attach the actual table so that we can look at the design in it? 

 

Thank you,

Melanie

 

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Re: DoE: disallowed combinations filter gives unexpected result

Here it is (hopefully).

 

 

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Re: DoE: disallowed combinations filter gives unexpected result

Got it - we'll look at it and get back to you.

Thanks,
Melanie
Highlighted

Re: DoE: disallowed combinations filter gives unexpected result

Apologies that you came across this issue. You are correct in your understanding - unfortunately, this is an issue that can sometimes occur with covariates and disallowed combinations. For this particular example, I would manually change surface roughness to a valid value (I think either choice shouldn't make a big difference, but if you're concerned, you can try Evaluate Design or Compare Designs to check).

 

I've made a note to get this addressed for a future release.


Cheers,

Ryan

View solution in original post

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Re: DoE: disallowed combinations filter gives unexpected result

OK, thanks. Then I'll wait for a future update and work manually for the time being.

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