Improvement of (Custom) Screening Design to lower number of experiments

[#1]

Dear JMP community,

I would like to characterize and optimize a biochemical reaction (enzyme assay). Therefore, I'm planning to do a screening first to scan for relevant factors. For now, I've decided to screen 8 factors (2x two-level categorical, 1x three-level categorical, 5x continuous).

I am familiar with the classical two-level screenings, but have never used a custom design before. My problem is my three-level categorical factor. It is the reason I chose a custom design and it seems to increase the necessary experiments a lot. Around 20 experiments for only main effects and over 50 experiments for main effects and two-factor interactions (with power over 0.8 for each factor).

Is there another option to find a compromise? I thought about trying to remove one level of the three-level categorical factor by pretests, only focusing on main effects for now, or dealing with a lower power of the test.

Thank you very much! 

(JMP Version: Student Edition 18)

[#2]

Yes, good suggestion.  This is why the specific situation needs to be understood before experimentation (situation diagnostics). Then it gets back to the compounds...what is really different between them?  Are they chemical compounds?  Then you might consider that you are experimenting of ratios or percentages of certain chemicals.  Which ones do you hypothesize are active?...and so the questions continue.