cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 
  • Don’t miss your chance to experience Discovery Summit Europe at our best available rate! Early bird registration through 31 Oct.
  • Graph Builder Toolbar streamlines interactive graphing. Creates shortcuts on Report and GraphBuilder Helpers toolbars. Download and install the extension.
  • JMP will suspend normal business operations for our Rest and Recharge Day on Friday, October 2, 2026.
    Regular business hours will resume on Monday, October 5, 2026.

Discussions

Solve problems, and share tips and tricks with other JMP users.
Choose Language Hide Translation Bar
Manisha
Level I

Query regarding design using categorical factors

JMP student edition 18
I was trying a custom design with 2 categorical factors and 3 levels. All effects -main and interaction show non significant p value despite using the recommended 9 run by the software.
1 REPLY 1
Victor_G
Super User

Re: Query regarding design using categorical factors

Hi @Manisha !

Welcome in the Community !

What is your objective (s) with this DoE : identify important effects, optimize your system, test the robustness of your system against noise factors, ... ? What are your factors ? Why are they only categorical with 3 levels ?

There are many possibles explanations to why you may not find any effects statistically significant:

  • High noise/experimental variability in response / inadequate measurement precision & repeatability : Have you any replicate runs in your design that may help estimate experimental variability ?
  • Factors ranges too small : in your case you're using only categorical factors, but are the levels studied different enough to see some variation ?
  • Missing of other important factors in the design
  • Inappropriate model and/or factors definition
  • Maybe these factors are indeed statistically non-significant and impactful on the response studied and with the levels tested.
  • ...

 

Regarding your design, I guess you have done all combinations involving your 2 three-levels factors (3x3). Maybe you could add some runs to have replicated runs and better estimate experimental variability, or adjust the p-value threshold depending on the power analysis : if you're very early in your study and regarding the small number of experiments, I doubt that a "standard" p-value threshold of 0.05 will enable to identify statistically significant effect (unless there are very strong effect sizes and very low noise/RMSE). You could use the Power analysis when designing your DoE with an estimate of anticipated noise in your response to adjust the size of the DoE and/or the alpha level (significance level).
What are the effects estimates ? Are they practically important ? Do they have a meaningful influence on the response ?

 

You can also read this similar topic (and responses) for information : Using DOE result as a quantitative or qualitative prediction (based on effect summary) 
With more information about your context it will be easier to help you,

Victor GUILLER

"It is not unusual for a well-designed experiment to analyze itself" (Box, Hunter and Hunter)

Recommended Articles